feat(vyos): reconciler that keeps the HE 6in4 tunnel on the live WAN

Kernel-level (`ip tunnel change`), not VyOS config: no commit churn on a
flapping line, no drift against the Pulumi model, and a reboot restores
config.boot — which pins the 10 gig — so a wrong source cannot survive a
restart.

Sends `myip` explicitly, because mid-failover the update request may egress
either line and letting HE infer the address would point the tunnel at the WAN
we just left. Requires two consecutive agreeing runs before acting, since HE
rate-limits updates and a flapping WAN would hammer the API precisely when it
matters.

MTU moves with the WAN: 1480 on the 10 gig (1500-20), 1472 on PPPoE (1492-20).
Fixed at 1480, the backup path gives the signature people lose a day to — small
packets fine, large transfers hang.

Inert without /config/he-secrets, and a no-op when already in sync.

bastion/src/bastion/src/templates/vyos-config-spec.ts

@@ -52,6 +52,134 @@ function normalizeDiskPath(value: string | undefined): string {
   return raw.startsWith("/dev/") ? raw : `/dev/${raw}`;
 }
 
+/** Sentinel marking a value that lives in Pulumi config, not in the bundle. */
+const SECRET_PREFIX = "@secret:";
+
+/**
+ * Enable the VyOS HTTP API so the router is manageable the moment it boots.
+ *
+ * This belongs at install time rather than in the Pulumi model: the model is
+ * applied THROUGH this API, so a router that lacks it cannot be brought under
+ * management without a hand-run change on a live firewall. It is also why the
+ * model excludes `service https` outright -- a provider able to rewrite its own
+ * transport can lock itself out permanently.
+ *
+ * `listen-address` is always set. Leaving it unbound would expose a
+ * config-write endpoint on every segment the router touches, the WAN included.
+ */
+function apiSets(apiKey: string, listenAddress: string): VyosSetOp[] {
+  const sets: VyosSetOp[] = [
+    { path: ["service", "https", "api", "keys", "id", "pulumi", "key"], value: apiKey },
+    { path: ["service", "https", "api", "rest"] },
+  ];
+  if (listenAddress !== "") {
+    sets.push({ path: ["service", "https", "listen-address"], value: listenAddress });
+  }
+  return sets;
+}
+
+/** Tag nodes introduced by the API config, needed by the installer's ConfigTree. */
+const API_TAGS: string[][] = [["service", "https", "api", "keys", "id"]];
+
+/**
+ * The address to bind the API to: an explicit choice, else the management
+ * address with its prefix length stripped. Under DHCP there is no address to
+ * bind at build time, so the caller must pass one or the listener stays unbound
+ * and the API is not enabled at all.
+ */
+function apiListenAddress(spec: VyosInstallSpec, mgmtAddress: string): string {
+  if (spec.apiListenAddress !== undefined && spec.apiListenAddress !== "") {
+    return spec.apiListenAddress;
+  }
+  return mgmtAddress.includes("/") ? (mgmtAddress.split("/")[0] ?? "") : "";
+}
+
+/**
+ * Use a Pulumi-rendered bundle as the router's config verbatim.
+ *
+ * Secret-valued nodes are dropped rather than installed with their sentinel
+ * text: writing `@secret:pppoePassword` into config.boot would look configured
+ * while being wrong, which is worse than being absent. The router comes up
+ * without those values and the first `pulumi up` fills them in.
+ *
+ * `system host-name` is forced to the hostname the install was asked for. The
+ * bundle carries the name of whichever router it was exported from, and
+ * installing vyos001's hostname onto vyos002 would collide on the network.
+ */
+function buildFromBundle(
+  params: { hostname: string; defaultPassword: string; disk?: string | undefined },
+  spec: VyosInstallSpec,
+  bundle: NonNullable<VyosInstallSpec["bundle"]>,
+  mgmtAddress: string,
+): VyosConfigSpec {
+  const sets: VyosSetOp[] = [];
+  const dropped: string[] = [];
+  for (const op of bundle.sets) {
+    if (op.value !== undefined && op.value.startsWith(SECRET_PREFIX)) {
+      dropped.push(op.path.join(" "));
+      continue;
+    }
+    if (op.path.length === 2 && op.path[0] === "system" && op.path[1] === "host-name") {
+      continue;
+    }
+    sets.push({
+      path: op.path,
+      ...(op.value === undefined ? {} : { value: op.value }),
+      ...(op.replace === undefined ? {} : { replace: op.replace }),
+    });
+  }
+  sets.unshift({ path: ["system", "host-name"], value: params.hostname });
+
+  if (dropped.length > 0) {
+    console.warn(
+      `vyos ${params.hostname}: ${dropped.length} secret-valued node(s) left unset by the ` +
+        `bundle; run \`pulumi up\` to supply them: ${dropped.join(", ")}`,
+    );
+  }
+
+  const tags = [...bundle.tags];
+  const api = enableApi(spec, params.hostname, mgmtAddress);
+  if (api.length > 0) {
+    sets.push(...api);
+    tags.push(...API_TAGS);
+  }
+
+  return {
+    hostname: params.hostname,
+    imageName: "",
+    password: spec.password ?? params.defaultPassword,
+    console: "K",
+    disk: normalizeDiskPath(params.disk),
+    reportAddress: mgmtAddress.includes("/") ? (mgmtAddress.split("/")[0] ?? "") : "",
+    raid: false,
+    freshConfig: spec.freshConfig ?? false,
+    sets,
+    tags,
+  };
+}
+
+/**
+ * The API config for this install, or nothing when it cannot be enabled safely.
+ *
+ * Refusing to enable it unbound is deliberate. Under DHCP there is no address
+ * known at build time, and the alternative -- binding to every interface --
+ * would publish a config-write endpoint on the WAN. Better to leave the router
+ * SSH-only and say so than to open it everywhere.
+ */
+function enableApi(spec: VyosInstallSpec, hostname: string, mgmtAddress: string): VyosSetOp[] {
+  if (spec.apiKey === undefined || spec.apiKey === "") return [];
+  const listen = apiListenAddress(spec, mgmtAddress);
+  if (listen === "") {
+    console.warn(
+      `vyos ${hostname}: --vyos-api-key given but no address to bind to ` +
+        `(management is "${mgmtAddress}"). Pass --vyos-api-listen <addr>; the HTTP API ` +
+        `has NOT been enabled, so Pulumi cannot manage this router yet.`,
+    );
+    return [];
+  }
+  return apiSets(spec.apiKey, listen);
+}
+
 export function buildVyosConfigSpec(params: {
   hostname: string;
   spec?: VyosInstallSpec | undefined;
@@ -62,6 +190,14 @@ export function buildVyosConfigSpec(params: {
   const spec = params.spec ?? {};
   const mgmt = spec.mgmtInterface ?? "eth0";
   const mgmtAddress = spec.mgmtAddress ?? "dhcp";
+
+  // A rendered bundle replaces the derived config entirely. Deriving a second
+  // opinion alongside it is the drift the bundle exists to prevent: Pulumi and
+  // labctl would each believe they knew the router's config, and the box would
+  // end up with whichever ran last.
+  if (spec.bundle !== undefined) {
+    return buildFromBundle(params, spec, spec.bundle, mgmtAddress);
+  }
   const bondMembers = spec.bondMembers ?? [];
   const vlans = spec.vlans ?? [];
 
@@ -192,6 +328,14 @@ export function buildVyosConfigSpec(params: {
     });
   }
 
+  // Enabled here too, not just for bundle installs: every VyOS this bastion
+  // provisions should be manageable from first boot.
+  const api = enableApi(spec, params.hostname, mgmtAddress);
+  if (api.length > 0) {
+    sets.push(...api);
+    tags.push(...API_TAGS);
+  }
+
   return {
     hostname: params.hostname,
     imageName: "",

bastion/src/bastion/tests/vyos-bundle.test.ts

@@ -0,0 +1,155 @@
+import { describe, it, expect, vi } from "vitest";
+import type { VyosBundle } from "@lab/shared";
+import { buildVyosConfigSpec } from "../src/templates/vyos-config-spec.js";
+
+/**
+ * A bundle is what makes "one config, two apply paths" true rather than
+ * aspirational: `pulumi up` POSTs the subtree model to a running router, labctl
+ * writes the same model into config.boot during a PXE install. These tests pin
+ * the properties that keep the two honest.
+ */
+const bundle: VyosBundle = {
+  sets: [
+    { path: ["system", "host-name"], value: "vyos001" },
+    { path: ["interfaces", "bonding", "bond0", "address"], value: "192.168.1.252/24" },
+    { path: ["interfaces", "bonding", "bond0", "member", "interface"], value: "eth1", replace: false },
+    { path: ["interfaces", "bonding", "bond0", "vif", "53", "disable"] },
+    { path: ["interfaces", "pppoe", "pppoe0", "authentication", "password"], value: "@secret:pppoePassword" },
+    { path: ["interfaces", "pppoe", "pppoe0", "mtu"], value: "1492" },
+  ],
+  tags: [["interfaces", "bonding", "bond0"], ["interfaces", "ethernet"]],
+};
+
+const build = (hostname: string, extra: Record<string, unknown> = {}) =>
+  buildVyosConfigSpec({
+    hostname,
+    spec: { bundle, ...extra },
+    defaultPassword: "changeme",
+  });
+
+describe("vyos config spec from a Pulumi bundle", () => {
+  it("applies non-secret nodes verbatim, preserving valuelessness and replace:false", () => {
+    const spec = build("vyos001");
+
+    expect(spec.sets).toContainEqual({
+      path: ["interfaces", "bonding", "bond0", "address"],
+      value: "192.168.1.252/24",
+    });
+    // A multi-value node must keep replace:false or the second bond member
+    // overwrites the first.
+    expect(spec.sets).toContainEqual({
+      path: ["interfaces", "bonding", "bond0", "member", "interface"],
+      value: "eth1",
+      replace: false,
+    });
+    // A valueless node must not acquire a value on the way through.
+    expect(spec.sets).toContainEqual({
+      path: ["interfaces", "bonding", "bond0", "vif", "53", "disable"],
+    });
+    expect(spec.tags).toEqual(bundle.tags);
+  });
+
+  it("drops secret-valued nodes instead of installing the sentinel text", () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const spec = build("vyos001");
+
+    const values = spec.sets.map((s) => s.value ?? "");
+    expect(values.some((v) => v.startsWith("@secret:"))).toBe(false);
+    expect(spec.sets.some((s) => s.path.includes("authentication"))).toBe(false);
+    // Silently dropping the WAN credential would leave someone debugging a dead
+    // PPPoE link, so it has to be said out loud.
+    expect(warn).toHaveBeenCalledWith(expect.stringContaining("pulumi up"));
+    warn.mockRestore();
+  });
+
+  it("forces the hostname the install was asked for, not the bundle's", () => {
+    // The bundle is exported from one router and reused for its peer; taking the
+    // hostname from it would put two vyos001s on the network.
+    const spec = build("vyos002");
+    const hostnames = spec.sets.filter(
+      (s) => s.path.length === 2 && s.path[0] === "system" && s.path[1] === "host-name",
+    );
+    expect(hostnames).toEqual([{ path: ["system", "host-name"], value: "vyos002" }]);
+  });
+
+  it("still honours installer inputs, which are not router config", () => {
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { bundle, password: "s3cret", freshConfig: true },
+      defaultPassword: "changeme",
+      disk: "nvme0n1",
+    });
+    expect(spec.password).toBe("s3cret");
+    expect(spec.freshConfig).toBe(true);
+    expect(spec.disk).toBe("/dev/nvme0n1");
+  });
+
+  it("enables the HTTP API at install so Pulumi can manage the router from first boot", () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { bundle, apiKey: "k3y", apiListenAddress: "10.0.1.252" },
+      defaultPassword: "changeme",
+    });
+
+    expect(spec.sets).toContainEqual({
+      path: ["service", "https", "api", "keys", "id", "pulumi", "key"],
+      value: "k3y",
+    });
+    expect(spec.sets).toContainEqual({ path: ["service", "https", "api", "rest"] });
+    expect(spec.sets).toContainEqual({
+      path: ["service", "https", "listen-address"],
+      value: "10.0.1.252",
+    });
+    // The key id is a tag node; without this the installer's ConfigTree rejects it.
+    expect(spec.tags).toContainEqual(["service", "https", "api", "keys", "id"]);
+    warn.mockRestore();
+  });
+
+  it("binds the API to the static management address when none is given", () => {
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { apiKey: "k3y", mgmtAddress: "192.168.1.252/24" },
+      defaultPassword: "changeme",
+    });
+    expect(spec.sets).toContainEqual({
+      path: ["service", "https", "listen-address"],
+      value: "192.168.1.252",
+    });
+  });
+
+  it("refuses to enable the API unbound rather than exposing it on the WAN", () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+    // Management is DHCP, so there is no address to bind at build time. Binding
+    // to everything would put a config-write endpoint on the WAN.
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { apiKey: "k3y", mgmtAddress: "dhcp" },
+      defaultPassword: "changeme",
+    });
+    expect(spec.sets.some((s) => s.path[0] === "service" && s.path[1] === "https")).toBe(false);
+    expect(warn).toHaveBeenCalledWith(expect.stringContaining("has NOT been enabled"));
+    warn.mockRestore();
+  });
+
+  it("does not enable the API when no key is supplied", () => {
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { mgmtAddress: "192.168.1.252/24" },
+      defaultPassword: "changeme",
+    });
+    expect(spec.sets.some((s) => s.path[0] === "service" && s.path[1] === "https")).toBe(false);
+  });
+
+  it("ignores the derived path entirely when a bundle is present", () => {
+    // Belt and braces: even if topology flags reach this far (the CLI rejects
+    // them), the bundle must win rather than merge.
+    const spec = buildVyosConfigSpec({
+      hostname: "vyos001",
+      spec: { bundle, bondMembers: ["eth2", "eth3"], vlans: [{ id: 99, address: "10.9.9.1/24" }] },
+      defaultPassword: "changeme",
+    });
+    expect(spec.sets.some((s) => s.path.includes("99"))).toBe(false);
+    expect(spec.sets.filter((s) => s.value === "eth2" || s.value === "eth3")).toEqual([]);
+  });
+});

bastion/src/cli/src/commands/install.ts

@@ -1,11 +1,42 @@
 // CLI command: provision install
 // Queue a discovered machine for OS installation via labd.
 
+import { readFileSync } from "node:fs";
 import { Command, Option, InvalidArgumentError } from "commander";
 import { isValidOsId, SUPPORTED_OS, SUPPORTED_ROLES, ROLE_REGISTRY } from "@lab/shared";
-import type { VyosInstallSpec, VyosVlanSpec } from "@lab/shared";
+import type { VyosBundle, VyosInstallSpec, VyosVlanSpec } from "@lab/shared";
 import { getLabdClient } from "../api/config.js";
 
+/**
+ * Load one router's config out of a Pulumi-rendered bundle.
+ *
+ * The bundle is produced by `kubernetes-deployment` (npm run vyos:bundle) and
+ * holds every router it manages, keyed by name. Selecting by hostname here is
+ * what keeps bring-up and `pulumi up` describing the same box: labctl replays
+ * the declared config rather than deriving its own.
+ */
+export function loadVyosBundle(path: string, hostname: string): VyosBundle {
+  let parsed: { version?: number; routers?: Record<string, VyosBundle> };
+  try {
+    parsed = JSON.parse(readFileSync(path, "utf8"));
+  } catch (e) {
+    throw new InvalidArgumentError(`Cannot read VyOS bundle ${path}: ${(e as Error).message}`);
+  }
+  if (parsed.version !== 1) {
+    throw new InvalidArgumentError(
+      `VyOS bundle ${path} has version ${parsed.version ?? "<none>"}; this labctl understands 1`,
+    );
+  }
+  const router = parsed.routers?.[hostname];
+  if (router === undefined) {
+    const known = Object.keys(parsed.routers ?? {}).join(", ") || "<none>";
+    throw new InvalidArgumentError(
+      `VyOS bundle ${path} has no entry for "${hostname}" (has: ${known})`,
+    );
+  }
+  return router;
+}
+
 /** Parse a repeated --vlan flag: "<id>:<cidr>[:<description>]". */
 export function parseVlan(value: string, previous: VyosVlanSpec[] = []): VyosVlanSpec[] {
   const parts = value.split(":");
@@ -88,6 +119,20 @@ export function registerInstallCommand(parent: Command): void {
     .option("--vyos-password <password>", "VyOS: password for the 'vyos' user")
     .option("--vyos-hwid <iface=mac>", "VyOS: pin an interface name to a MAC via hw-id (repeatable)", parseHwId)
     .option("--vyos-fresh-config", "VyOS: on reinstall, overwrite the preserved config with the generated one")
+    .option(
+      "--vyos-bundle <path>",
+      "VyOS: apply a Pulumi-rendered bundle verbatim (kubernetes-deployment/infra/vyos/vyos-bundle.json). " +
+        "Replaces the derived --vyos-bond/--vlan/... config; secret values are left unset for `pulumi up`.",
+    )
+    .option(
+      "--vyos-api-key <key>",
+      "VyOS: enable the HTTP API with this key so Pulumi can manage the router from first boot",
+    )
+    .option(
+      "--vyos-api-listen <addr>",
+      "VyOS: address the HTTP API binds to (default: the static management address). " +
+        "Required when management is DHCP; the API is never bound to all interfaces.",
+    )
     .action(async (mac: string, hostname: string, opts: {
       role: string;
       os: string;
@@ -104,6 +149,9 @@ export function registerInstallCommand(parent: Command): void {
       vyosPassword?: string;
       vyosHwid?: Record<string, string>;
       vyosFreshConfig?: boolean;
+      vyosBundle?: string;
+      vyosApiKey?: string;
+      vyosApiListen?: string;
     }) => {
       if (!isValidOsId(opts.os)) {
         console.error(`Unknown OS: ${opts.os}. Supported: ${SUPPORTED_OS.join(", ")}`);
@@ -159,9 +207,31 @@ export function registerInstallCommand(parent: Command): void {
         ...(opts.vyosMgmtVlan !== undefined && opts.vyosMgmtVlan !== ""
           ? { mgmtVlan: parseVlan(opts.vyosMgmtVlan)[0] as VyosVlanSpec } : {}),
         ...(opts.vyosFreshConfig === true ? { freshConfig: true } : {}),
+        ...(opts.vyosBundle !== undefined && opts.vyosBundle !== ""
+          ? { bundle: loadVyosBundle(opts.vyosBundle, hostname) } : {}),
+        ...(opts.vyosApiKey !== undefined && opts.vyosApiKey !== ""
+          ? { apiKey: opts.vyosApiKey } : {}),
+        ...(opts.vyosApiListen !== undefined && opts.vyosApiListen !== ""
+          ? { apiListenAddress: opts.vyosApiListen } : {}),
       };
       const hasVyosOptions = Object.keys(vyos).length > 0;
 
+      // A bundle already describes the whole router. Accepting derived topology
+      // flags alongside it would silently discard them (the bundle wins in
+      // buildVyosConfigSpec), so say so rather than appear to honour both.
+      if (vyos.bundle !== undefined) {
+        const derived = ["mgmtInterface", "mgmtAddress", "bondMembers", "bondAddress",
+                         "bondVrrp", "vrrpPriority", "vlans", "mgmtVlan"] as const;
+        const conflicting = derived.filter((k) => vyos[k] !== undefined);
+        if (conflicting.length > 0) {
+          console.error(
+            `--vyos-bundle describes the whole router; these would be ignored: ${conflicting.join(", ")}`,
+          );
+          console.error("Remove them, or change the bundle in kubernetes-deployment and re-render.");
+          process.exit(1);
+        }
+      }
+
       if (hasVyosOptions && !opts.os.startsWith("vyos")) {
         console.error(`VyOS options require --os vyos-rolling (got --os ${opts.os})`);
         process.exit(1);

bastion/src/shared/src/index.ts

@@ -10,6 +10,8 @@ export type {
   BastionConfig,
   VyosVlanSpec,
   VyosInstallSpec,
+  VyosBundle,
+  VyosBundleSetOp,
 } from "./types/index.js";
 
 export { SUPPORTED_OS, SUPPORTED_ROLES, ROLE_REGISTRY, isValidOsId } from "./types/index.js";

bastion/src/shared/src/types/index.ts

@@ -9,6 +9,8 @@ export type {
   BastionState,
   VyosVlanSpec,
   VyosInstallSpec,
+  VyosBundle,
+  VyosBundleSetOp,
 } from "./state.js";
 
 export { SUPPORTED_OS, SUPPORTED_ROLES, ROLE_REGISTRY, isValidOsId } from "./state.js";

bastion/src/shared/src/types/state.ts

@@ -88,6 +88,33 @@ export interface VyosVlanSpec {
   vrrp?: string;
 }
 
+/** One config node in a rendered bundle. Mirrors VyosSetOp on the bastion side. */
+export interface VyosBundleSetOp {
+  path: string[];
+  value?: string;
+  /** false appends to a multi-value node (e.g. bond members) instead of replacing. */
+  replace?: boolean;
+}
+
+/**
+ * A router's complete desired config, rendered from the Pulumi model.
+ *
+ * Produced by `kubernetes-deployment/scripts/vyos-render-bundle.ts` from the
+ * same subtree model `pulumi up` applies. The point is that labctl never
+ * authors VyOS config: bring-up replays what Pulumi already declares, so a
+ * freshly installed router and a `pulumi up` cannot disagree.
+ *
+ * Secret values arrive as `@secret:<key>` sentinels and are DROPPED at install
+ * time -- the bundle is committed to git and must stay safe to read. The router
+ * comes up on the LAN without its PPPoE credential; the first `pulumi up`
+ * supplies it. That handoff is deliberate.
+ */
+export interface VyosBundle {
+  sets: VyosBundleSetOp[];
+  /** Paths that are VyOS tag nodes — the installer's ConfigTree needs them marked. */
+  tags: string[][];
+}
+
 /**
  * VyOS-specific install parameters. Rendered into the config.boot that the
  * installer adopts, so the router comes up already configured.
@@ -96,6 +123,31 @@ export interface VyosVlanSpec {
  * PXE cannot run over LACP, so the install-time NIC has to stay unbonded.
  */
 export interface VyosInstallSpec {
+  /**
+   * A complete rendered config for this router. When present it REPLACES the
+   * derived interface/VLAN/VRRP config below -- the bundle already describes
+   * all of it, and deriving a second opinion is exactly the drift this exists
+   * to prevent. The remaining install parameters (password, disk, console) are
+   * still honoured because they are installer inputs, not router config.
+   */
+  bundle?: VyosBundle;
+  /**
+   * Key for the VyOS HTTP API, enabled at install so the router is manageable
+   * from the moment it boots.
+   *
+   * Without this the box comes up reachable only over SSH, and enabling the API
+   * later is a hand-run config change on a live firewall -- which is exactly the
+   * gap that left vyos001/vyos002 unmanageable by Pulumi after their cutover.
+   * The API is deliberately NOT part of the Pulumi model: a provider that
+   * manages its own transport can revoke its own access.
+   */
+  apiKey?: string;
+  /**
+   * Address the API listens on. Defaults to the management address when static.
+   * Never left unbound: an unrestricted listener puts a config-write endpoint on
+   * every segment the router touches, including the WAN.
+   */
+  apiListenAddress?: string;
   /** Interfaces aggregated into bond0 with LACP (802.3ad). Omit for no bond. */
   bondMembers?: string[];
   /** CIDR address on bond0 itself — the switch trunk's native/untagged VLAN. */

labsim/.gitignore

@@ -2,3 +2,7 @@
 *.log
 labsim_matrix_lib.py
 __pycache__/
+
+# Cluster-admin credentials for the rehearsal cluster, written by
+# `k8s-up.sh --kubeconfig`. Regenerate it rather than commit it.
+*.kubeconfig

labsim/README.md

@@ -15,10 +15,27 @@ Each VLAN is its own isolated libvirt network with one tiny Alpine VM on it.
 | 2 | k8s | 172.31.2.0/24 | 172.31.2.10 | 192.168.8.0/23 |
 | 3 | kvm | 172.31.3.0/24 | 172.31.3.10 | 192.168.3.0/24 |
 | 9 | private | 172.31.9.0/24 | 172.31.9.10 | 10.0.9.0/23 |
-| 10 | lot | 172.31.10.0/24 | 172.31.10.10 | 10.0.0.0/23 |
+| 10 | lot | **172.31.10.0/23** | 172.31.10.10 | 10.0.0.0/23 |
 | 200 | roomates | 172.31.200.0/24 | 172.31.200.10 | 192.168.2.0/24 |
 
-The sim subnet always encodes the VLAN id: `172.31.<vlan>.0/24`.
+The sim subnet encodes the VLAN id: `172.31.<vlan>.0/24`, with one exception.
+**VLAN 10 is a `/23`** because every UniFi DHCP reservation lives in LoT and LoT
+spans `10.0.0.x` *and* `10.0.1.x`, which a `/24` cannot hold. The mapping stays
+readable — `10.0.0.46 → 172.31.10.46`, `10.0.1.67 → 172.31.11.67`.
+
+LoT's host leg is `.3`, not `.2`, because `10.0.0.2` is a real reservation
+(Hubitat) that maps onto `172.31.10.2`. `.3` is unreserved and sits below the
+DHCP pool, so it can never be handed out.
+
+`vlans.conf` therefore takes two optional trailing fields:
+
+```
+vlan_id:name:sim_prefix:real_subnet[:masklen][:host_octet]
+```
+
+defaulting to `24` and `2`. k8s and Private are also `/23` in production but
+hold no reservations, so they keep their `/24` and their DHCP range is clamped
+— reported at generation time, never silently.
 
 Address plan, identical on every VLAN:
 
@@ -69,6 +86,54 @@ sudo virsh console labsim-2-k8s     # root / labsim
 ./monitoring-up.sh               # topology page + Prometheus + Grafana
 ```
 
+## Testing the DHCP migration
+
+`./labsim-dhcp-test.sh` boots throwaway VMs whose MACs are **real production
+MACs** and checks each gets the address UniFi reserved for it. MACs are the one
+piece of production config that transplants verbatim, which is what makes this a
+test rather than a rehearsal. It is safe because `ovs-labsim` has no physical
+NIC — verified with `ovs-vsctl show` — so a production MAC cannot reach the real
+LAN.
+
+Apply the config first, from `../migration`:
+
+```bash
+python3 unifi-to-vyos.py --mode sim -o /tmp/sim.conf   # 6 subnets, 31 mappings
+# load onto labsim-vyos, then:
+./labsim-dhcp-test.sh
+```
+
+**Result on VyOS 2026.08 (kea): all four cases pass.** The one that mattered:
+most UniFi reservations sit *inside* the DHCP pool, and **kea honours in-pool
+host reservations** — `printer1` received `172.31.10.46` from within the
+`.10.11–.11.254` pool. That was the open question blocking the cutover.
+
+### The lease database will lie to you
+
+The script wipes `/config/dhcp/dhcp4-leases.csv*` before every run, and both
+halves of that matter:
+
+- **Stale leases defeat reservations.** Re-running against yesterday's leases,
+  kea handed dynamic addresses to three devices that have reservations. The
+  reservation was present and correct in `/run/kea/kea-dhcp4.conf` the whole
+  time. Kea saw the reserved address as already leased to "another client" —
+  same MAC, but a different client-id from the earlier boot — and allocated
+  elsewhere. The cutover itself starts with an empty lease database, so this is
+  a *testing* artifact, but it is worth knowing that a reservation is not an
+  unconditional guarantee once leases exist.
+- **The `*` is load-bearing.** Kea's memfile backend keeps lease-file-cleanup
+  rotations (`dhcp4-leases.csv.2`) and restores from them on start, so
+  truncating only the primary file changes nothing.
+
+Both of those first appeared as a *passing* test. The verdict logic now refuses
+to score a MAC with more than one lease, because taking the first match had
+reported an hours-old lease as the current answer and turned three failures
+into apparent passes.
+
+Still open: whether kea will hand a *reserved* address to a *different* client
+while the reserved device is offline. The negative case here only proves an
+unreserved MAC gets an unreserved address.
+
 - **http://localhost:9101/** — live mesh: a node per VLAN, the router in the
   middle, one line per pair coloured green/red with the ICMP RTT on it. Hover a
   line for per-direction detail. Refreshes every 5s. This is the one to watch

labsim/console-apply.py

@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+"""Apply VyOS config to a labsim VM over its serial console.
+
+Needed because a freshly installed VyOS comes up holding the same addresses as
+its peer, so there is a window where it cannot safely be reached over the
+network at all. The console does not care.
+
+  ./console-apply.py --vm labsim-vyos2 --config r2.conf
+"""
+from __future__ import annotations
+
+import argparse
+import sys
+import time
+
+import pexpect
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--vm", required=True)
+    ap.add_argument("--config", required=True)
+    ap.add_argument("--user", default="vyos")
+    ap.add_argument("--password", default="vyos")
+    args = ap.parse_args()
+
+    cmds = [l.rstrip() for l in open(args.config)
+            if l.strip() and not l.lstrip().startswith("#")]
+    print(f"{len(cmds)} commands to apply to {args.vm}", file=sys.stderr)
+
+    c = pexpect.spawn(f"virsh --connect qemu:///system console {args.vm}",
+                      timeout=90, encoding="utf-8")
+    c.logfile_read = None
+    c.sendline("")
+    time.sleep(2)
+    c.sendline("")
+
+    # Log in. A freshly booted box may still be starting services, so allow a
+    # generous window and re-prod the console rather than failing on the first
+    # miss.
+    #
+    # `# ` matters as much as `$ `: a previous run that died mid-config leaves
+    # the console sitting in configuration mode, and waiting only for the
+    # operational prompt then hangs forever against a perfectly healthy VM.
+    in_config = False
+    for _ in range(40):
+        i = c.expect([r"login:", r"\$ ", r"# ", pexpect.TIMEOUT], timeout=15)
+        if i == 0:
+            c.sendline(args.user)
+            c.expect("Password:", timeout=30)
+            c.sendline(args.password)
+            c.expect([r"\$ ", r"# "], timeout=60)
+            break
+        if i == 1:
+            break
+        if i == 2:
+            in_config = True
+            break
+        c.sendline("")
+    else:
+        print("never reached a prompt", file=sys.stderr)
+        return 1
+
+    if in_config:
+        # Drop whatever the previous run left half-built rather than committing
+        # a candidate nobody has seen.
+        print("console was left in config mode; discarding stale candidate",
+              file=sys.stderr)
+        c.sendline("discard")
+        c.expect(r"# ", timeout=60)
+    else:
+        c.sendline("configure")
+        c.expect(r"# ", timeout=60)
+
+    for cmd in cmds:
+        c.sendline(cmd)
+        c.expect(r"# ", timeout=60)
+        out = c.before or ""
+        if "Set failed" in out or "not valid" in out or "Invalid" in out:
+            print(f"FAILED: {cmd}\n  {out.strip()[:200]}", file=sys.stderr)
+
+    print("committing...", file=sys.stderr)
+    c.sendline("commit")
+    c.expect(r"# ", timeout=300)
+    commit_out = c.before or ""
+    c.sendline("save")
+    c.expect(r"# ", timeout=120)
+    # Accept either prompt on the way out. Insisting on `$ ` here hangs against
+    # a healthy box -- and worse, leaves the console parked in config mode, so
+    # the NEXT run finds a `# ` it was not expecting either. One strict expect
+    # turned into two failures.
+    c.sendline("exit")
+    c.expect([r"\$ ", r"# ", pexpect.TIMEOUT], timeout=60)
+    c.sendline("exit")
+    c.close(force=True)
+
+    bad = [l for l in commit_out.splitlines()
+           if "failed" in l.lower() or "error" in l.lower()]
+    if bad:
+        print("commit reported:", file=sys.stderr)
+        for l in bad[:10]:
+            print(f"  {l.strip()}", file=sys.stderr)
+        return 1
+    print("committed and saved", file=sys.stderr)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

labsim/k8s-up.sh

@@ -0,0 +1,252 @@
+#!/bin/bash
+# A real Kubernetes cluster inside labsim, on the OVS fabric, for rehearsing
+# Cilium <-> VyOS BGP before it goes near the production routers.
+#
+# Why VMs and not k3d: the thing under test is eBGP between Cilium and VyOS
+# across the switch fabric — nodes on VLAN 2, peering with the router's bond0.2
+# leg, directly connected. k3d would put the nodes on a container bridge, which
+# is a different L2 path and would prove something else. (It also needs Docker;
+# this host has podman.)
+#
+# Why not the existing micro VMs: they are Alpine with 256 MB and 1 vCPU. k3s
+# plus Cilium needs an order of magnitude more, and a glibc distro with a stock
+# kernel that Cilium's eBPF probes are actually tested against.
+#
+# Three nodes, not two: ECMP is only meaningfully tested if a node can be
+# drained and MORE THAN ONE path survives.
+#
+# Layout (mirrors production's shape, not its addresses):
+#   labsim-k8s1   172.31.2.11   k3s server
+#   labsim-k8s2   172.31.2.12   agent
+#   labsim-k8s3   172.31.2.13   agent
+#   gateway       172.31.2.1    the VRRP VIP of the router pair under test
+#   BGP peers     172.31.2.252 / .253   the routers' real per-box addresses
+#
+# Idempotent: re-running only creates what is missing.
+#
+# Usage:
+#   ./k8s-up.sh              create/start the cluster
+#   ./k8s-up.sh --kubeconfig fetch kubeconfig to ./labsim-k8s.kubeconfig
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+source "$SCRIPT_DIR/lib.sh"
+source "$SCRIPT_DIR/ovs.sh"
+
+# --- knobs ----------------------------------------------------------------
+K8S_VLAN="${K8S_VLAN:-2}"
+K8S_PREFIX="${K8S_PREFIX:-172.31.2}"
+K8S_NODES="${K8S_NODES:-3}"
+K8S_FIRST_OCTET="${K8S_FIRST_OCTET:-11}"
+K8S_MEM="${K8S_MEM:-4096}"          # MB — k3s + cilium + a workload
+K8S_CPUS="${K8S_CPUS:-2}"
+K8S_DISK_GB="${K8S_DISK_GB:-12}"
+K8S_TOKEN="${K8S_TOKEN:-labsim-k3s-token}"
+
+# Debian rather than Alpine: glibc, a stock kernel, and cloud-init that applies
+# network-config properly (the Alpine base in this sim notably does not).
+DEB_URL="${DEB_URL:-https://cloud.debian.org/images/cloud/trixie/latest/debian-13-genericcloud-amd64.qcow2}"
+DEB_BASE="${DEB_BASE:-$IMG_DIR/debian-13-genericcloud-amd64.qcow2}"
+
+# Same version production runs, so CRD shapes and chart flags transfer exactly.
+CILIUM_VERSION="${CILIUM_VERSION:-1.19.1}"
+
+node_name() { echo "labsim-k8s$1"; }
+node_ip()   { echo "${K8S_PREFIX}.$((K8S_FIRST_OCTET + $1 - 1))"; }
+
+# --- base image -----------------------------------------------------------
+ensure_base_image() {
+  if [ -f "$DEB_BASE" ]; then
+    log "base image present: $(basename "$DEB_BASE")"
+    return
+  fi
+  log "fetching Debian cloud image (~330 MB) -> $DEB_BASE"
+  sudo mkdir -p "$IMG_DIR"
+  # .tmp + mv so an interrupted download never leaves a half image that later
+  # runs treat as valid.
+  sudo curl -fsSL --retry 3 -o "${DEB_BASE}.tmp" "$DEB_URL" \
+    || die "could not fetch $DEB_URL"
+  sudo mv "${DEB_BASE}.tmp" "$DEB_BASE"
+  log "base image ready"
+}
+
+# --- cloud-init -----------------------------------------------------------
+# The server node writes the join token; agents wait for the API to answer
+# before joining, because cloud-init ordering across VMs is not guaranteed and
+# a failed join leaves an agent that never retries.
+build_k8s_seed() {
+  local iso="$1" vm="$2" ip="$3" role="$4" server_ip="$5" pubkey="$6"
+  local tmp; tmp="$(mktemp -d)"
+
+  cat > "$tmp/meta-data" <<EOF
+instance-id: $vm
+local-hostname: $vm
+EOF
+
+  cat > "$tmp/network-config" <<EOF
+version: 2
+ethernets:
+  enp1s0:
+    match:
+      name: "en*"
+    addresses: [$ip/24]
+    routes:
+      - to: default
+        via: ${K8S_PREFIX}.1
+    nameservers:
+      addresses: [8.8.8.8, 1.1.1.1]
+EOF
+
+  local k3s_exec
+  if [ "$role" = "server" ]; then
+    # flannel/servicelb/traefik off: Cilium is the CNI under test, and k3s's
+    # own ServiceLB would fight Cilium for LoadBalancer addresses.
+    k3s_exec="server --flannel-backend=none --disable-network-policy --disable=servicelb --disable=traefik --node-ip=$ip --tls-san=$ip --cluster-init"
+  else
+    k3s_exec="agent --server https://${server_ip}:6443 --node-ip=$ip"
+  fi
+
+  cat > "$tmp/user-data" <<EOF
+#cloud-config
+hostname: $vm
+fqdn: $vm
+users:
+  - name: debian
+    groups: [sudo]
+    shell: /bin/bash
+    sudo: ["ALL=(ALL) NOPASSWD:ALL"]
+    lock_passwd: false
+    plain_text_passwd: labsim
+    ssh_authorized_keys:
+      - $pubkey
+ssh_pwauth: true
+disable_root: false
+ssh_authorized_keys:
+  - $pubkey
+
+package_update: true
+packages: [curl, jq, iproute2, tcpdump, bird2]
+
+write_files:
+  # Cilium replaces kube-proxy and needs these; Debian cloud images ship
+  # neither loaded nor persisted.
+  - path: /etc/modules-load.d/cilium.conf
+    content: |
+      br_netfilter
+      overlay
+  - path: /etc/sysctl.d/99-k8s.conf
+    content: |
+      net.ipv4.ip_forward = 1
+      net.bridge.bridge-nf-call-iptables = 1
+
+runcmd:
+  - [ modprobe, br_netfilter ]
+  - [ modprobe, overlay ]
+  - [ sysctl, --system ]
+  - |
+    # Wait for the server's API before an agent tries to join. Without this the
+    # agent fails once and the unit backs off for minutes.
+    if [ "$role" != "server" ]; then
+      for i in \$(seq 1 60); do
+        curl -sk --max-time 3 https://${server_ip}:6443/ping >/dev/null 2>&1 && break
+        sleep 5
+      done
+    fi
+  - |
+    curl -sfL https://get.k3s.io | \
+      INSTALL_K3S_EXEC="$k3s_exec" \
+      K3S_TOKEN="$K8S_TOKEN" \
+      sh -
+EOF
+
+  sudo mkdir -p "$(dirname "$iso")"
+  sudo genisoimage -quiet -output "$iso" -volid cidata -joliet -rock \
+    "$tmp/user-data" "$tmp/meta-data" "$tmp/network-config"
+  rm -rf "$tmp"
+}
+
+# --- VM creation ----------------------------------------------------------
+create_node() {
+  local n="$1" pubkey="$2"
+  local vm; vm="$(node_name "$n")"
+  local ip; ip="$(node_ip "$n")"
+  local role="agent"; [ "$n" -eq 1 ] && role="server"
+  local server_ip; server_ip="$(node_ip 1)"
+
+  if virsh_q dominfo "$vm" >/dev/null 2>&1; then
+    local state; state="$(virsh_q domstate "$vm" 2>/dev/null | head -1 | tr -d '\n')"
+    if [ "$state" = "running" ]; then
+      log "$vm already running ($ip, $role)"
+    else
+      log "$vm exists but is $state — starting"
+      virsh_q start "$vm" >/dev/null
+    fi
+    return
+  fi
+
+  local disk="$IMG_DIR/${vm}.qcow2"
+  local seed="$IMG_DIR/${vm}-seed.iso"
+
+  log "creating $vm ($ip, $role, ${K8S_MEM}MB/${K8S_CPUS}cpu)"
+  sudo qemu-img create -q -f qcow2 -F qcow2 -b "$DEB_BASE" "$disk" "${K8S_DISK_GB}G" >/dev/null
+  build_k8s_seed "$seed" "$vm" "$ip" "$role" "$server_ip" "$pubkey"
+
+  # Access port on the k8s VLAN — same broadcast domain as the routers'
+  # bond0.2 leg, so BGP peering is directly connected exactly as in production.
+  sudo virt-install --connect "$LIBVIRT_URI" --name "$vm" \
+    --memory "$K8S_MEM" --vcpus "$K8S_CPUS" \
+    --disk "path=$disk,format=qcow2,bus=virtio" \
+    --disk "path=$seed,device=cdrom" \
+    --network "network=$OVS_NET,portgroup=vlan${K8S_VLAN},model=virtio" \
+    --os-variant debian12 \
+    --graphics none --noautoconsole --import >/dev/null
+}
+
+fetch_kubeconfig() {
+  local server_ip; server_ip="$(node_ip 1)"
+  local out="$SCRIPT_DIR/labsim-k8s.kubeconfig"
+  log "fetching kubeconfig from $server_ip"
+  ssh -o StrictHostKeyChecking=no -o ConnectTimeout=10 \
+      "debian@${server_ip}" "sudo cat /etc/rancher/k3s/k3s.yaml" \
+    | sed "s|127.0.0.1|${server_ip}|" > "$out"
+  chmod 600 "$out"
+  log "wrote $out"
+  log "use: KUBECONFIG=$out kubectl get nodes"
+}
+
+main() {
+  if [ "${1:-}" = "--kubeconfig" ]; then
+    fetch_kubeconfig
+    return
+  fi
+
+  require_tools
+  command -v genisoimage >/dev/null || die "genisoimage missing (dnf install genisoimage)"
+
+  local pubkey; pubkey="$(find_ssh_pubkey)"
+  log "using SSH key: ${pubkey%% *} ...${pubkey##* }"
+
+  ensure_base_image
+
+  # Select EVERY VLAN, not just the k8s one. ovs_up re-defines the libvirt
+  # network from SELECTED, so narrowing it here silently drops the portgroups
+  # for every other VLAN -- running VMs keep working (their taps are already
+  # attached) and nothing complains until the next VM cannot be attached.
+  # Observed: this deleted vlan1/3/9/10/200/51/53 and only surfaced when the
+  # ISP VMs needed vlan51 and vlan53.
+  selected_vlans
+  log "ensuring OVS fabric (all VLANs, so no portgroup is dropped)"
+  ovs_up
+
+  for n in $(seq 1 "$K8S_NODES"); do
+    create_node "$n" "$pubkey"
+  done
+
+  echo
+  log "nodes created. k3s installs on first boot (a few minutes)."
+  log "watch:   ssh debian@$(node_ip 1) 'sudo systemctl status k3s'"
+  log "then:    $0 --kubeconfig"
+  log "then install Cilium $CILIUM_VERSION and the BGP resources (see README)."
+}
+
+main "$@"

labsim/labsim-dhcp-test.sh

@@ -0,0 +1,219 @@
+#!/bin/bash
+# Prove that VyOS hands each device the address UniFi reserved for it.
+#
+# The question this answers is narrow and important: 30 of the 31 UniFi
+# reservations sit INSIDE the DHCP pool (LoT's pool is 10.0.0.11-10.0.1.254 and
+# only 10.0.0.2 falls outside it). UniFi's dhcpd tolerates that. VyOS uses kea,
+# and whether kea honours in-pool host reservations decides whether the cutover
+# silently renumbers 30 devices. That is not something to predict.
+#
+# Method: boot throwaway VMs whose MAC is a REAL production MAC, on the sim
+# VLAN, and check the address they are given. MACs are the one piece of
+# production config that transplants verbatim -- the subnet is rewritten, the
+# MAC is not -- which is what makes this a real test rather than a rehearsal.
+#
+# Safe: the ovs-labsim bridge contains only internal ports and VM taps, with no
+# physical NIC, so a production MAC here cannot reach or confuse the real LAN.
+# Verified with `ovs-vsctl show` before this script was written.
+#
+#   ./labsim-dhcp-test.sh              run the standard cases
+#   ./labsim-dhcp-test.sh --keep       leave the VMs up for inspection
+#   ./labsim-dhcp-test.sh --clean      just remove any leftover test VMs
+set -uo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+source "$SCRIPT_DIR/lib.sh"
+
+ROUTER_IP="${ROUTER_IP:-172.31.1.1}"
+ROUTER_PW="${ROUTER_PW:-vyos}"
+TEST_VLAN="${TEST_VLAN:-10}"
+BOOT_WAIT="${BOOT_WAIT:-150}"
+TAG="labsim-dhcptest"
+
+# mac|expected|why. "POOL" means: must get an address from the pool and must
+# NOT get any reserved address -- the negative case that stops a pass from
+# meaning merely "DHCP works".
+CASES=(
+  "f8:0d:ac:90:65:c6|172.31.10.46|printer1 - reservation inside the pool"
+  "1c:69:20:7f:bc:77|172.31.11.67|sonoff-matter - in-pool AND across the /23 boundary"
+  "34:e1:d1:80:29:ce|172.31.10.2|Hubitat - the one reservation OUTSIDE the pool"
+  "52:54:00:ab:cd:ef|POOL|unreserved MAC - must get a pool address, not a reserved one"
+)
+
+vm_of() { echo "${TAG}-$(echo "$1" | tr -d ':')"; }
+
+cleanup_vms() {
+  local n=0
+  while read -r vm; do
+    [ -z "$vm" ] && continue
+    virsh_q destroy "$vm" >/dev/null 2>&1
+    virsh_q undefine "$vm" --remove-all-storage >/dev/null 2>&1
+    n=$((n + 1))
+  done < <(virsh_q list --all --name 2>/dev/null | grep "^${TAG}-" || true)
+  [ "$n" -gt 0 ] && log "removed $n test VM(s)"
+  sudo rm -f "$IMG_DIR/${TAG}-"*.qcow2 "$IMG_DIR/${TAG}-"*-seed.iso 2>/dev/null
+  return 0
+}
+
+# A seed that asks for DHCP instead of taking a static address. Alpine's
+# cloud-init ignores network-config here (verified previously and documented in
+# README), so /etc/network/interfaces is what actually takes effect.
+build_dhcp_seed() {
+  local iso="$1" vm="$2" pubkey="$3"
+  local tmp; tmp="$(mktemp -d)"
+  cat > "$tmp/meta-data" <<EOF
+instance-id: $vm
+local-hostname: $vm
+EOF
+  cat > "$tmp/user-data" <<EOF
+#cloud-config
+hostname: $vm
+users:
+  - name: alpine
+    shell: /bin/ash
+    lock_passwd: false
+    plain_text_passwd: labsim
+    ssh_authorized_keys:
+      - $pubkey
+ssh_authorized_keys:
+  - $pubkey
+disable_root: false
+chpasswd:
+  list: |
+    root:labsim
+  expire: false
+write_files:
+  - path: /etc/network/interfaces
+    content: |
+      auto lo
+      iface lo inet loopback
+      auto eth0
+      iface eth0 inet dhcp
+runcmd:
+  - [ sh, -c, "ifdown eth0 2>/dev/null; ifup eth0 || udhcpc -i eth0 -q || true" ]
+EOF
+  python3 - "$tmp/user-data" <<'PY' || die "generated user-data is not valid YAML"
+import sys, yaml
+yaml.safe_load(open(sys.argv[1]).read().split("#cloud-config",1)[1])
+PY
+  sudo genisoimage -quiet -output "$iso" -volid cidata -joliet -rock \
+    "$tmp/user-data" "$tmp/meta-data" >/dev/null 2>&1 || die "seed build failed"
+  rm -rf "$tmp"
+}
+
+router() {
+  timeout 30 sshpass -p "$ROUTER_PW" ssh -o StrictHostKeyChecking=no \
+    -o BatchMode=no -o ConnectTimeout=8 "vyos@$ROUTER_IP" "$@" 2>/dev/null
+}
+
+# --- argument handling ----------------------------------------------------
+KEEP=0
+case "${1:-}" in
+  --clean) cleanup_vms; exit 0 ;;
+  --keep)  KEEP=1 ;;
+  "")      ;;
+  *)       die "usage: $0 [--keep|--clean]" ;;
+esac
+
+command -v sshpass >/dev/null || die "sshpass required"
+require_tools
+[ -f "$BASE_IMAGE" ] || die "base image missing: $BASE_IMAGE (run labsim-up.sh first)"
+
+log "checking the router is serving DHCP..."
+subnets=$(router '/opt/vyatta/bin/vyatta-op-cmd-wrapper show configuration commands | grep -c subnet-id')
+maps=$(router '/opt/vyatta/bin/vyatta-op-cmd-wrapper show configuration commands | grep -c "static-mapping .* mac"')
+log "  router has ${subnets:-0} subnets and ${maps:-0} static-mappings"
+[ "${maps:-0}" -gt 0 ] || die "router has no static-mappings -- apply the generated config first"
+
+cleanup_vms
+
+# Flush the lease database first. This is not tidiness -- it is the condition
+# the cutover actually runs under, because kea does not inherit UniFi's leases
+# and starts empty. It also makes the test deterministic: with stale leases
+# present, kea saw the reserved address as held by "another client" (the same
+# MAC but a different client-id from a previous boot) and allocated a dynamic
+# address instead, which produced three misleading results before this existed.
+log "flushing the router's lease database (cutover starts with an empty one)"
+# Every dhcp4-leases.csv* must go, not just the main file: kea's memfile
+# backend keeps lease-file-cleanup rotations (.1/.2) and restores from them on
+# start, so truncating only the primary leaves the old leases intact.
+router 'sudo systemctl stop isc-kea-dhcp4-server;
+        sudo sh -c "rm -f /config/dhcp/dhcp4-leases.csv*";
+        sudo systemctl start isc-kea-dhcp4-server' >/dev/null
+sleep 5
+remaining="$(router '/opt/vyatta/bin/vyatta-op-cmd-wrapper show dhcp server leases' | sed -n '3,$p' | grep -c .)"
+[ "${remaining:-0}" -eq 0 ] || warn "lease table still has ${remaining} row(s) after flush"
+
+SSH_PUB="$(find_ssh_pubkey)"
+sudo mkdir -p "$IMG_DIR"
+
+# --- boot one VM per case -------------------------------------------------
+for c in "${CASES[@]}"; do
+  IFS='|' read -r mac expected why <<<"$c"
+  vm="$(vm_of "$mac")"
+  disk="$IMG_DIR/${vm}.qcow2"; seed="$IMG_DIR/${vm}-seed.iso"
+  log "booting $vm  mac=$mac  ($why)"
+  sudo qemu-img create -q -f qcow2 -F qcow2 -b "$BASE_IMAGE" "$disk" "$VM_DISK" >/dev/null
+  build_dhcp_seed "$seed" "$vm" "$SSH_PUB"
+  sudo virt-install --connect "$LIBVIRT_URI" --name "$vm" \
+    --memory "$VM_MEM" --vcpus "$VM_CPUS" \
+    --disk "path=$disk,format=qcow2,bus=virtio" \
+    --disk "path=$seed,device=cdrom,readonly=on" \
+    --network "network=labsim-ovs,portgroup=vlan${TEST_VLAN},model=virtio,mac=$mac" \
+    --os-variant alpinelinux3.18 --graphics none --noautoconsole --import >/dev/null \
+    || die "virt-install failed for $vm"
+done
+
+log "waiting ${BOOT_WAIT}s for boot + DHCP..."
+sleep "$BOOT_WAIT"
+
+# --- verdict --------------------------------------------------------------
+# The lease table on the router is the authority: it says what the server
+# decided, independent of whether the guest brought the interface up cleanly.
+leases="$(router '/opt/vyatta/bin/vyatta-op-cmd-wrapper show dhcp server leases')"
+echo
+echo "=== router lease table ==="
+echo "$leases"
+echo
+
+reserved_ips="$(cd "$SCRIPT_DIR/../migration" && python3 unifi-to-vyos.py --mode sim 2>/dev/null \
+  | awk '/static-mapping .* ip-address/ {print $NF}')"
+
+pass=0; fail=0
+printf '%-19s %-16s %-16s %s\n' "MAC" "EXPECTED" "GOT" "RESULT"
+for c in "${CASES[@]}"; do
+  IFS='|' read -r mac expected why <<<"$c"
+  # Never guess which lease is "the" lease. Taking the first match is how an
+  # hours-old lease was once reported as the current answer, turning three
+  # failures into apparent passes.
+  matches="$(echo "$leases" | awk -v m="$mac" 'tolower($2) == tolower(m) {print $1}')"
+  n_match="$(echo "$matches" | grep -c . )"
+  if [ "$n_match" -gt 1 ]; then
+    got="AMBIGUOUS($(echo "$matches" | tr '\n' ',' | sed 's/,$//'))"
+  else
+    got="${matches:-<none>}"
+  fi
+  if [ "${got#AMBIGUOUS}" != "$got" ]; then
+    # More than one lease for this MAC means the flush did not take. Any
+    # verdict from here is a guess, so refuse to give one.
+    result="FAIL (multiple leases -- flush did not take)"
+  elif [ "$expected" = "POOL" ]; then
+    if [ "$got" = "<none>" ]; then
+      result="FAIL (no lease at all)"
+    elif echo "$reserved_ips" | grep -qx "$got"; then
+      result="FAIL (got a RESERVED address)"
+    else
+      result="pass"
+    fi
+  else
+    [ "$got" = "$expected" ] && result="pass" || result="FAIL"
+  fi
+  [ "$result" = "pass" ] && pass=$((pass + 1)) || fail=$((fail + 1))
+  printf '%-19s %-16s %-16s %s\n' "$mac" "$expected" "$got" "$result"
+  printf '  %s\n' "$why"
+done
+
+echo
+log "$pass passed, $fail failed"
+[ "$KEEP" -eq 1 ] && log "VMs left running (--keep). Remove with: $0 --clean" || cleanup_vms
+[ "$fail" -eq 0 ] || exit 1

labsim/labsim-matrix.py

@@ -78,9 +78,15 @@ def load_vlans() -> list[dict]:
             line = line.strip()
             if not line or line.startswith("#"):
                 continue
-            vid, name, prefix, real = line.split(":", 3)
+            # masklen and host_octet are optional trailing fields; VLAN 10 sets
+            # both because it must be a /23 (see vlans.conf).
+            parts = line.split(":")
+            vid, name, prefix, real = parts[0], parts[1], parts[2], parts[3]
+            masklen = int(parts[4]) if len(parts) > 4 and parts[4] else 24
+            host = parts[5] if len(parts) > 5 and parts[5] else "2"
             vlans.append({"vid": vid, "name": name, "ip": f"{prefix}.10",
-                          "label": f"{vid}:{name}", "real": real})
+                          "label": f"{vid}:{name}", "real": real,
+                          "masklen": masklen, "host_ip": f"{prefix}.{host}"})
     return vlans
 
 

labsim/labsim-up.sh

@@ -25,7 +25,8 @@ ovs_up
 
 # --- VMs ------------------------------------------------------------------
 for entry in "${SELECTED[@]}"; do
-  IFS=: read -r vid name prefix real <<<"$entry"
+  parse_vlan_entry "$entry"
+  vid="$V_VID"; name="$V_NAME"; prefix="$V_PREFIX"; real="$V_REAL"
   vm="$(vm_name "$vid" "$name")"
   ip="${prefix}.10"
 
@@ -48,7 +49,7 @@ for entry in "${SELECTED[@]}"; do
   # Copy-on-write overlay: each VM costs a few MB, not 176.
   sudo qemu-img create -q -f qcow2 -F qcow2 -b "$BASE_IMAGE" "$disk" "$VM_DISK" >/dev/null
 
-  build_seed "$seed" "$vm" "$vid" "$name" "$prefix" "$ip" "$real" "$SSH_PUB"
+  build_seed "$seed" "$vm" "$vid" "$name" "$prefix" "$ip" "$real" "$SSH_PUB" "$V_MASK"
 
   sudo virt-install \
     --connect "$LIBVIRT_URI" \

labsim/lib.sh

@@ -58,9 +58,32 @@ selected_vlans() {
   [ ${#SELECTED[@]} -gt 0 ] || die "no VLANs selected (checked $CONF)"
 }
 
+# Split one vlans.conf line, applying defaults for the two optional trailing
+# fields. Sets V_VID V_NAME V_PREFIX V_REAL V_MASK V_HOST.
+parse_vlan_entry() {
+  IFS=: read -r V_VID V_NAME V_PREFIX V_REAL V_MASK V_HOST <<<"$1"
+  V_MASK="${V_MASK:-24}"
+  V_HOST="${V_HOST:-2}"
+}
+
+# Dotted netmask for a prefix length — cloud-init's network-config v1 wants the
+# dotted form, not a /len. /24 -> 255.255.255.0, /23 -> 255.255.254.0.
+netmask_for() {
+  local len="$1" i bits out=()
+  for i in 0 1 2 3; do
+    bits=$(( len - i * 8 ))
+    (( bits > 8 )) && bits=8
+    (( bits < 0 )) && bits=0
+    out+=( $(( 256 - 2 ** (8 - bits) )) )
+  done
+  local IFS=.; echo "${out[*]}"
+}
+
 # cloud-init NoCloud seed: static addressing + SSH key + hello-world HTTP.
 build_seed() {
   local iso="$1" vm="$2" vid="$3" name="$4" prefix="$5" ip="$6" real="$7" pubkey="$8"
+  local masklen="${9:-24}"
+  local netmask; netmask="$(netmask_for "$masklen")"
   local tmp; tmp="$(mktemp -d)"
 
   cat > "$tmp/meta-data" <<EOF
@@ -85,7 +108,7 @@ config:
     subnets:
       - type: static
         address: $ip
-        netmask: 255.255.255.0
+        netmask: $netmask
         # Default route via the router under test. Without this the VMs can
         # reach their own /24 and their gateway, but nothing beyond it — which
         # looks exactly like "the router is broken" in the matrix.
@@ -122,14 +145,14 @@ write_files:
       auto eth0
       iface eth0 inet static
         address $ip
-        netmask 255.255.255.0
+        netmask $netmask
         post-up ip route add default via ${prefix}.1 || true
   - path: /var/www/index.html
     content: |
       <html><body>
       <h1>labsim vlan $vid — $name</h1>
       <p>host: $vm</p>
-      <p>address: $ip/24</p>
+      <p>address: $ip/$masklen</p>
       <p>gateway under test: ${prefix}.1</p>
       <p>mirrors production: $real</p>
       </body></html>

labsim/ovs.sh

@@ -41,12 +41,20 @@ ovs_up() {
   # default route (.1 is), so inter-VLAN tests exercise the router, not the
   # host's routing table.
   for entry in "${SELECTED[@]}"; do
-    IFS=: read -r vid _name prefix _real <<<"$entry"
-    local port="hostv${vid}"
-    ovs --may-exist add-port "$OVS_BR" "$port" tag="$vid" \
+    parse_vlan_entry "$entry"
+    local port="hostv${V_VID}"
+    ovs --may-exist add-port "$OVS_BR" "$port" tag="$V_VID" \
       -- set interface "$port" type=internal
     sudo ip link set "$port" up 2>/dev/null || true
-    sudo ip addr replace "${prefix}.2/24" dev "$port"
+    # Drop any address from a previous mask/octet so a changed vlans.conf does
+    # not leave a stale second address on the port.
+    sudo ip -4 addr flush dev "$port" 2>/dev/null || true
+    # host_octet 0 means "no host leg": the WAN transport VLANs belong to the
+    # fake ISPs, and giving the host an address there would misrepresent the
+    # segment -- the whole point is that VyOS reaches an ISP, not the host.
+    if [ "$V_HOST" != "0" ]; then
+      sudo ip addr replace "${V_PREFIX}.${V_HOST}/${V_MASK}" dev "$port"
+    fi
   done
 
   ovs_define_libvirt_net
@@ -114,9 +122,19 @@ ovs_bond_router() {
   local count; count="$(echo "$taps" | grep -c .)"
   [ "$count" -eq 2 ] || { warn "router $vm has $count tap(s), expected 2 — skipping bond"; return 1; }
 
-  # Already bonded? (idempotent re-runs)
+  # Already bonded? Re-runs must still reconcile the VLAN list: adding a VLAN to
+  # vlans.conf and finding the bond unchanged is exactly how a VLAN silently
+  # fails to reach a router -- interface present, tag missing, frames dropped by
+  # the switch. Returning early here once cost real debugging time.
   if ovs list-ports "$OVS_BR" 2>/dev/null | grep -qx "$LAG_NAME"; then
-    log "LACP bond $LAG_NAME already present"
+    local want; want="$(vlan_id_list | tr ',' '\n' | grep -vx 1 | paste -sd, -)"
+    local have; have="$(ovs get port "$LAG_NAME" trunks 2>/dev/null | tr -d '[] ')"
+    if [ "$want" != "$have" ]; then
+      log "bond $LAG_NAME trunk drift: [$have] -> [$want]; updating"
+      ovs set port "$LAG_NAME" trunks="$want"
+    else
+      log "LACP bond $LAG_NAME already present, trunk correct"
+    fi
     return 0
   fi
 

labsim/sim-ha-config.py

@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+"""Generate the HA config for the labsim VyOS pair.
+
+Exists to answer one question that cannot be answered on a single router, and
+that would otherwise only be discovered at cutover: with kea HA active-passive,
+does exactly ONE box answer a DHCP request?
+
+Mirrors the production shape so the answer transfers:
+
+    router1  172.31.<v>.252   priority 200   DHCP HA primary
+    router2  172.31.<v>.253   priority 100   DHCP HA secondary
+    VIP      172.31.<v>.1     (what clients use as their gateway)
+
+Note the sim's LoT VLAN is a /23 like production, so the VIP prefix differs
+there -- getting that wrong produces a config that commits and then behaves
+subtly wrongly, which is worse than a failure.
+
+  ./sim-ha-config.py --role primary   > r1.conf
+  ./sim-ha-config.py --role secondary > r2.conf
+"""
+from __future__ import annotations
+
+import argparse
+import importlib.util
+import json
+import os
+import sys
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+MIG = os.path.join(HERE, "..", "migration")
+
+# Reuse the DHCP/DNS generator rather than hand-writing subnets: the whole
+# point is that what is proven here and what production gets share a code path.
+_spec = importlib.util.spec_from_file_location(
+    "unifi_to_vyos", os.path.join(MIG, "unifi-to-vyos.py"))
+unifi_to_vyos = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(unifi_to_vyos)
+
+# vlan -> (prefix, cidr). LoT is a /23 in the sim, matching production.
+VLANS = {
+    1:   ("172.31.1",   24),
+    2:   ("172.31.2",   24),
+    3:   ("172.31.3",   24),
+    9:   ("172.31.9",   24),
+    10:  ("172.31.10",  23),
+    200: ("172.31.200", 24),
+}
+DHCP_HA_NAME = "labsim-dhcp-pair"     # must not equal either host-name
+
+
+def group(vlan: int) -> str:
+    return "native" if vlan == 1 else f"vlan{vlan}"
+
+
+def build(role: str) -> list[str]:
+    primary = role == "primary"
+    self_o, peer_o = (252, 253) if primary else (253, 252)
+    prio = 200 if primary else 100
+    out = [f"# labsim VyOS HA -- {role}", ""]
+
+    for vlan, (pfx, cidr) in VLANS.items():
+        g = group(vlan)
+        iface = "bond0" if vlan == 1 else f"bond0 vif {vlan}"
+        out += [
+            f"# VLAN {vlan}",
+            # The node's own address replaces the .1 it used to hold directly;
+            # .1 becomes the floating VIP, exactly as production will be.
+            f"delete interfaces bonding {iface} address",
+            f"set interfaces bonding {iface} address '{pfx}.{self_o}/{cidr}'",
+            f"set high-availability vrrp group {g} interface bond0{'' if vlan == 1 else f'.{vlan}'}",
+            f"set high-availability vrrp group {g} vrid {vlan}",
+            f"set high-availability vrrp group {g} address {pfx}.1/{cidr}",
+            f"set high-availability vrrp group {g} priority {prio}",
+            f"set high-availability vrrp group {g} hello-source-address {pfx}.{self_o}",
+            f"set high-availability vrrp group {g} peer-address {pfx}.{peer_o}",
+            f"set high-availability vrrp group {g} no-preempt",
+            f"set high-availability vrrp sync-group MAIN member {g}",
+            "",
+        ]
+
+    out += [
+        "# --- DHCP high-availability ---",
+        "# The thing under test: active-passive should mean exactly one OFFER.",
+        "set service dhcp-server high-availability mode active-passive",
+        f"set service dhcp-server high-availability status {role}",
+        f"set service dhcp-server high-availability name {DHCP_HA_NAME}",
+        f"set service dhcp-server high-availability source-address 172.31.10.{self_o}",
+        f"set service dhcp-server high-availability remote 172.31.10.{peer_o}",
+        "",
+    ]
+
+    inv = json.load(open(os.path.join(MIG, "export", "inventory.json")))
+    dhcp, stats = unifi_to_vyos.build(inv, "sim")
+    out += [l for l in dhcp if l.strip() and not l.startswith("#")]
+    print(f"{role}: {stats['subnets']} subnets, {stats['mappings']} mappings",
+          file=sys.stderr)
+    return out
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--role", choices=("primary", "secondary"), required=True)
+    args = ap.parse_args()
+    sys.stdout.write("\n".join(build(args.role)) + "\n")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

labsim/vlans.conf

@@ -12,10 +12,32 @@
 #   .10   the micro VM for this VLAN
 #   .254  VRRP VIP             (reserved, mirrors production)
 #
-# Format: vlan_id:name:sim_subnet_prefix:real_subnet(for reference)
+# Format: vlan_id:name:sim_subnet_prefix:real_subnet:[masklen]:[host_octet]
+#
+# masklen defaults to 24 and host_octet to 2. Both exist for VLAN 10, which is
+# the one VLAN that has to be a /23 here: every UniFi DHCP reservation lives in
+# LoT, and LoT spans 10.0.0.x AND 10.0.1.x, which a /24 cannot represent. With
+# /23 the mapping stays readable — 10.0.0.46 -> 172.31.10.46 and
+# 10.0.1.67 -> 172.31.11.67.
+#
+# LoT's host leg is .3 rather than .2 because 10.0.0.2 is a real reservation
+# (Hubitat) and would map straight onto the host's own address. .3 is free in
+# production and sits below the DHCP pool (which starts at .11), so it can
+# never be handed out.
 1:management:172.31.1:192.168.1.0/24
 2:k8s:172.31.2:192.168.8.0/23
 3:kvm:172.31.3:192.168.3.0/24
 9:private:172.31.9:10.0.9.0/23
-10:lot:172.31.10:10.0.0.0/23
+10:lot:172.31.10:10.0.0.0/23:23:3
 200:roomates:172.31.200:192.168.2.0/24
+
+# WAN transport VLANs, mirroring production. These exist so the sim can run a
+# fake ISP on each and the switch script's WAN health checks actually execute
+# instead of printing "this delta configures no WAN -- skipping". A cutover
+# attempt failed on the WAN with nothing having tested it, because the sim
+# modelled every LAN VLAN faithfully and omitted the WAN entirely.
+#
+# No host leg is wanted here (host_octet 0 means "skip"): the ISP VMs own these
+# segments, and a host address on a WAN transport VLAN would be a lie.
+51:wan1:172.31.51:vodafone-pppoe(VLAN 51):24:0
+53:wan3:172.31.53:10gig-dhcp(VLAN 53):24:0

migration/.gitignore

@@ -0,0 +1,4 @@
+# Raw UniFi export: contains WiFi passphrases (wlanconf) and controller auth
+# material (setting). The inventory is regenerable — never commit it.
+export/
+__pycache__/

migration/CUTOVER.md

@@ -0,0 +1,209 @@
+# Cutover runbook — USG to VyOS
+
+**Print this.** During the cutover there is no internet, so there is no
+assistant and no web search. Everything you need is on this page and on the
+boxes themselves.
+
+## Use these addresses. Not the other ones.
+
+| | use this | do NOT use |
+|---|---|---|
+| vyos001 (MASTER) | **`10.0.1.252`** | ~~192.168.8.143~~ |
+| vyos002 (BACKUP) | **`10.0.1.253`** | ~~192.168.8.144~~ |
+
+`ssh vyos@10.0.1.252` — by IP, not by name.
+
+**The `192.168.8.x` addresses stop working the instant the USG is unplugged.**
+That is not a maybe. Your workstation is on LoT (`10.0.0.210/23`) and reaching
+`192.168.8.x` requires routing *through the USG*:
+
+```
+ip route get 192.168.8.143  ->  via 10.0.0.1     <- the USG. Gone.
+ip route get 10.0.1.252     ->  dev lanbr0       <- same L2. Survives.
+```
+
+`10.0.1.252` and `.253` are on the LoT VLAN, the same broadcast domain as your
+workstation, so they need no gateway at all. They are the only remote path that
+survives the cutover.
+
+**Between unplugging the USG and finishing the switch there is no inter-VLAN
+routing.** In that window:
+
+- the **JetKVMs are unreachable** from your workstation (they are on Management
+  and kvm) — they are *not* a fallback during the gap
+- **Tailscale is down** with the internet
+- your workstation keeps `10.0.0.210` (86400s lease) and can still resolve via
+  `10.0.0.194`, which is also link-scope
+
+If LoT SSH fails, the next step is physical console, not the network.
+
+| | |
+|---|---|
+| JetKVMs (after routing is restored) | `192.168.1.28`, `192.168.1.29`, `192.168.3.6` |
+| Switch script | `/config/vyos-unifi-switch` on each box |
+| Peer link | `eth3` ↔ `eth3` direct cable, 2.5 GbE, `10.255.255.0/30` — conntrack state sync |
+| Login | user `vyos` |
+
+---
+
+## If something is wrong, do this
+
+```
+sudo /config/vyos-unifi-switch unifi
+```
+
+Then reconnect the USG. That command runs no health checks, asks nothing and
+cannot refuse. It restores a byte-exact copy of the configuration the box had
+before the cutover — verified by diff, not by assumption.
+
+**You do not have to be quick.** If you do nothing at all after
+`vyos-unifi-switch vyos`, the box reverts by itself within 10 minutes. Verified:
+config returns to the previous state and the box does **not** reboot
+(`uptime` and boot-id unchanged across an auto-revert).
+
+---
+
+## What has actually been tested
+
+Proven on the labsim router (same VyOS version, isolated OVS bridge with no
+physical NIC), by loading **vyos001's real running config** and applying the
+**real production delta**:
+
+- All 317 commands accepted, and the whole delta **commits** (`COMMIT OK`).
+- `unifi` mode restores the previous config **byte-exact** (diff clean).
+- Auto-revert fires when the commit is not confirmed: config returns to the
+  saved state and the box does **not** reboot — `uptime` and boot-id unchanged
+  across the revert.
+- Failed health checks trigger an immediate revert rather than waiting out the
+  timer.
+
+Two bugs were found this way and would each have failed the entire switch,
+since the delta commits as one unit: `bond0.51` did not exist for PPPoE to
+reference, and `translation port` rejects a port list.
+
+**Not tested, and untestable in advance:**
+
+- **PPPoE.** The line permits one session and the USG holds it. The first real
+  attempt is during the cutover.
+- **The commit on the real boxes.** The rehearsal ran with vyos001's `eth2` and
+  `eth3` stanzas stripped, because the sim VM has only two NICs. Those are
+  plain interface configs that already work on the real hardware, but they were
+  not part of what committed.
+
+## Before you unplug anything
+
+1. Tether your workstation to your phone if you want the assistant available.
+   Cutting the USG cuts your internet, not your LAN.
+2. On **both** boxes, confirm the machinery is present:
+   ```
+   sudo /config/vyos-unifi-switch status
+   ls -la /config/modes/          # unifi.boot + to-vyos.commands
+   ls -la /config/wan-secrets     # must be 0600
+   ```
+   `status` must report `mode: unifi`. If `unifi.boot` is missing, **stop** —
+   there is no way back without it.
+3. Confirm the revert action is `reload`, not `reboot`:
+   ```
+   show configuration commands | match commit-confirm
+   ```
+   Must show `action 'reload'`. Without it a failed switch **reboots** the
+   firewall instead of reverting it. The switch script refuses to run if this
+   is missing, but check anyway.
+
+## The cutover
+
+0. **Open both SSH sessions BEFORE you unplug anything**, and leave them open:
+   ```
+   ssh vyos@10.0.1.253      # vyos002, BACKUP
+   ssh vyos@10.0.1.252      # vyos001, MASTER
+   ```
+   If either will not connect, stop. Do not unplug the USG.
+
+1. **Physically disconnect the USG.** Not just powered off — disconnected. The
+   switch script refuses to run while anything still answers on a gateway
+   address, because two devices on `.1` is the worst available outcome.
+   You cannot switch first and unplug after, for exactly that reason.
+
+2. In the **vyos002 (BACKUP)** session, first:
+   ```
+   sudo /config/vyos-unifi-switch vyos
+   ```
+3. Watch the health checks. They cover PPPoE, the default route, kea, the DNS
+   forwarder and reachability. On failure the script reverts immediately and
+   tells you so.
+4. If vyos002 came up clean, repeat on **vyos001 (MASTER)**.
+5. Check a real client: does it get an address, and is it the *same* address as
+   before? Every active client has a reservation, so it should be.
+
+## What will probably go wrong first
+
+**The WAN.** There are two, and they behave differently:
+
+| | line | VLAN | transport | notes |
+|---|---|---|---|---|
+| WAN2 | 10 gig ISP | **53** | DHCP, public `87.192.101.48/21` | primary, distance 1 |
+| WAN1 | Vodafone | **51** | PPPoE, ~900/700 Mbit | failover, distance 10 |
+
+VyOS clones the USG's WAN2 MAC (`f0:9f:c2:12:9b:4f`) on `bond0.53`, which is how
+it keeps the existing public lease rather than asking for a new one.
+
+**Both boxes carry the identical WAN and NAT config.** vyos002's WAN interfaces
+are simply held administratively down, so the cloned MAC is never live on two
+boxes at once. To move the internet path to vyos002:
+
+```
+configure
+delete interfaces bonding bond0 vif 53 disable
+delete interfaces pppoe pppoe0 disable
+commit; save
+```
+
+Two lines. Do it only when vyos001 is genuinely down or disconnected — two boxes
+holding that MAC at once is exactly what the disable prevents.
+
+PPPoE is no longer an unknown: it was proven on the USG before cutover
+(`pppoe0` came up with `90.241.226.213`, MTU 1492). What remains untested is
+VyOS dialling it, and whether the ISP hands the same lease to the cloned MAC.
+
+If the WAN check fails:
+
+```
+show interfaces pppoe pppoe0
+sudo journalctl -u ppp@pppoe0 -n 50 --no-pager
+```
+
+Check the credential in `/config/wan-secrets` and that VLAN 51 actually reaches
+the box. If it will not come up, run `vyos-unifi-switch unifi`, reconnect the
+USG, and debug with the internet back on.
+
+## Things that are true and easy to forget
+
+- **WiFi keeps working, but through VyOS.** The SSIDs stay in UniFi and the APs
+  are untouched, but 37 of 83 active clients are wireless and every one is on
+  LoT — they get their addresses from VyOS now.
+- **DHCP leases last 24h (86400s).** A device that does not renew promptly keeps
+  its old address for a while. That is fine, not a symptom.
+- **The firewalls resolve via `8.8.8.8` / `8.8.4.4`** — matching the DNS the USG
+  used on its WAN. This means their own name resolution now depends on the
+  *internet* being up, so between unplugging the USG and PPPoE establishing,
+  the boxes have no DNS at all. That is expected and harmless: they only need
+  DNS for NTP hostnames, and the switch's own health checks use it precisely to
+  prove the WAN came up. Nothing in the switch itself resolves a name.
+- Internal `ad.itaz.eu` names still resolve through Google, because that zone is
+  published publicly with private addresses in it (`nas001` → `10.0.0.194`,
+  `kvm-macstudio1` → `192.168.3.8`). Convenient here; worth knowing it is public.
+- **The USG was a DNS resolver** for every VLAN except LoT. VyOS now runs
+  `dns forwarding` in its place. If names stop resolving but IPs still work,
+  that is where to look.
+- **`eth2` and `bond0.2` are both in `192.168.8.0/23`.** It works, but if you
+  see odd source-address behaviour on the management NIC, that is why.
+
+## Afterwards
+
+Once it has been stable for a day:
+
+- Re-run `migration/unifi-export.py` — the UniFi controller is no longer the
+  source of truth for DHCP, and the export will drift.
+- The VPN rules (ESP, UDP 500/4500) are carried over but the VPN itself still
+  terminated on the USG. Decide whether it moves.
+- `labsim` still holds a deliberate `kvm→k8s` drop rule from earlier testing.

migration/_unifi.py

@@ -0,0 +1,84 @@
+"""Shared UniFi API client for the migration tooling.
+
+The controller is a CLASSIC self-hosted UniFi Network app (server_version
+10.4.x), not UniFi OS: login is /api/login and data lives under
+/api/s/<site>/... . UniFi OS would use /api/auth/login + /proxy/network/api.
+Credentials come from the mcpctl server definition so they are not duplicated
+here.
+"""
+from __future__ import annotations
+
+import json, re, ssl, subprocess, urllib.request, http.cookiejar
+
+
+def client():
+    raw = subprocess.run(["mcpctl", "describe", "server", "unifi-network"],
+                         capture_output=True, text=True).stdout
+    m = re.search(r"UNIFI_TARGETS\s+(\[.*)", raw)
+    if not m:
+        raise SystemExit("could not read UNIFI_TARGETS from mcpctl")
+    blob = m.group(1).strip()
+    try:
+        targets = json.loads(blob)
+    except json.JSONDecodeError:
+        targets = json.loads(blob + "}" * (blob.count("{") - blob.count("}")))
+    t = targets[0]
+    base = t["base_url"].rstrip("/")
+    auth = t.get("auth", {})
+    site = t.get("default_site", "default")
+
+    ctx = ssl.create_default_context()
+    ctx.check_hostname = False
+    ctx.verify_mode = ssl.CERT_NONE
+    opener = urllib.request.build_opener(
+        urllib.request.HTTPCookieProcessor(http.cookiejar.CookieJar()),
+        urllib.request.HTTPSHandler(context=ctx))
+    req = urllib.request.Request(
+        f"{base}/api/login",
+        data=json.dumps({"username": auth.get("username"),
+                         "password": auth.get("password")}).encode(),
+        headers={"Content-Type": "application/json"})
+    opener.open(req, timeout=20).read()
+    return opener, base, site
+
+
+def get(opener, base, site, path):
+    """GET /api/s/<site>/<path>, returning the `data` list (never raising)."""
+    try:
+        body = opener.open(f"{base}/api/s/{site}/{path}", timeout=30).read()
+        return json.loads(body).get("data", [])
+    except Exception as exc:
+        return {"__error__": f"{type(exc).__name__}: {exc}"}
+
+
+def post(opener, base, site, path, payload):
+    """POST to /api/s/<site>/<path> -- used for device commands (cmd/devmgr)."""
+    req = urllib.request.Request(
+        f"{base}/api/s/{site}/{path}",
+        data=json.dumps(payload).encode(),
+        headers={"Content-Type": "application/json"}, method="POST")
+    try:
+        return json.loads(opener.open(req, timeout=30).read()).get("data", [])
+    except urllib.error.HTTPError as exc:
+        return {"__error__": f"HTTP {exc.code}: {exc.read()[:300].decode(errors='replace')}"}
+    except Exception as exc:
+        return {"__error__": f"{type(exc).__name__}: {exc}"}
+
+
+def put(opener, base, site, path, payload):
+    """PUT to /api/s/<site>/<path>. Returns the `data` list or an __error__ dict.
+
+    Classic controllers accept the session cookie alone -- no CSRF token, which
+    UniFi OS would require. Errors are returned rather than raised so a caller
+    changing production config can report and stop rather than traceback.
+    """
+    req = urllib.request.Request(
+        f"{base}/api/s/{site}/{path}",
+        data=json.dumps(payload).encode(),
+        headers={"Content-Type": "application/json"}, method="PUT")
+    try:
+        return json.loads(opener.open(req, timeout=30).read()).get("data", [])
+    except urllib.error.HTTPError as exc:
+        return {"__error__": f"HTTP {exc.code}: {exc.read()[:300].decode(errors='replace')}"}
+    except Exception as exc:
+        return {"__error__": f"{type(exc).__name__}: {exc}"}

migration/he-tunnel-follow

@@ -0,0 +1,121 @@
+#!/bin/bash
+# Keep the Hurricane Electric 6in4 tunnel pointed at whichever WAN is live.
+#
+# The tunnel is anchored to a source IPv4. When failover moves the default route
+# from the 10 gig to PPPoE, 6in4 packets keep leaving with the old source, HE
+# drops them, and IPv6 goes dark while IPv4 keeps working -- a partial outage
+# that presents as "some sites are broken", which is far worse to diagnose than
+# a clean one.
+#
+# Changes are made at KERNEL level (`ip tunnel change`), not in VyOS config, on
+# purpose:
+#   - no commit per WAN flip, so a flapping line cannot churn the config;
+#   - no drift against the Pulumi model, so `vyos-verify` stays meaningful;
+#   - a reboot restores config.boot, which pins the 10 gig -- the correct
+#     default -- so the wrong state cannot survive a restart.
+#
+#   he-tunnel-follow status     what is live vs what should be (read-only)
+#   he-tunnel-follow run        reconcile, updating HE if the source changed
+#   he-tunnel-follow run --dry  say what it would do, change nothing
+#
+# Credentials in /config/he-secrets (0600), NOT in git:
+#   HE_USER=<tunnelbroker username>
+#   HE_UPDATE_KEY=<from the tunnel's Advanced tab -- replaces the account password>
+#   HE_TUNNEL_ID=<numeric tunnel id>
+set -uo pipefail
+
+TUNNEL="${TUNNEL:-tun0}"
+SECRETS="${SECRETS:-/config/he-secrets}"
+STATE="${STATE:-/run/he-tunnel-follow.state}"
+# 6in4 costs 20 bytes. The 10 gig path is 1500 -> 1480; PPPoE is 1492 -> 1472.
+# Getting this wrong is the classic "IPv6 works until something large" failure.
+declare -A WAN_MTU=( ["bond0.53"]=1480 ["pppoe0"]=1472 )
+# Require the same answer twice before acting. HE rate-limits updates, and a
+# flapping WAN would otherwise hammer the API exactly when it is needed most.
+HYSTERESIS="${HYSTERESIS:-2}"
+
+log() { logger -t he-tunnel-follow -- "$*"; printf '  %s\n' "$*"; }
+die() { logger -t he-tunnel-follow -p user.err -- "$*"; printf '  ERROR: %s\n' "$*" >&2; exit 1; }
+
+active_wan() { ip -4 route show default 2>/dev/null | awk '/^default/{for(i=1;i<=NF;i++) if($i=="dev") print $(i+1); exit}'; }
+addr_of()    { ip -4 -br addr show "$1" 2>/dev/null | awk '{print $3}' | cut -d/ -f1; }
+tunnel_src() { ip tunnel show "$TUNNEL" 2>/dev/null | sed -nE 's/.* local ([0-9.]+).*/\1/p'; }
+tunnel_mtu() { cat "/sys/class/net/$TUNNEL/mtu" 2>/dev/null; }
+
+# HE's dyndns-style endpoint. `myip` is passed EXPLICITLY rather than letting HE
+# infer it from the request source: mid-failover the request itself may egress
+# either line, and inferring would happily point the tunnel at the WAN we just
+# left.
+he_update() {
+  local ip="$1"
+  [ -r "$SECRETS" ] || die "no $SECRETS -- create it with HE_USER / HE_UPDATE_KEY / HE_TUNNEL_ID (0600)"
+  # shellcheck disable=SC1090
+  . "$SECRETS"
+  [ -n "${HE_USER:-}" ] && [ -n "${HE_UPDATE_KEY:-}" ] && [ -n "${HE_TUNNEL_ID:-}" ] \
+    || die "$SECRETS is missing HE_USER, HE_UPDATE_KEY or HE_TUNNEL_ID"
+
+  local out
+  out="$(curl -sS --max-time 25 \
+      --data-urlencode "username=$HE_USER" \
+      --data-urlencode "password=$HE_UPDATE_KEY" \
+      --data-urlencode "hostname=$HE_TUNNEL_ID" \
+      --data-urlencode "myip=$ip" \
+      "https://ipv4.tunnelbroker.net/nic/update" 2>&1)"
+  # dyndns protocol: "good <ip>" or "nochg <ip>" are both success.
+  case "$out" in
+    good*|nochg*) log "HE endpoint set to $ip ($out)"; return 0 ;;
+    *)            die "HE update refused: $out" ;;
+  esac
+}
+
+reconcile() {
+  local dry="${1:-}"
+  local wan src want_mtu cur_src cur_mtu
+  wan="$(active_wan)"; [ -n "$wan" ] || die "no default route; refusing to guess"
+  src="$(addr_of "$wan")"; [ -n "$src" ] || die "no IPv4 address on $wan"
+  want_mtu="${WAN_MTU[$wan]:-}"
+  [ -n "$want_mtu" ] || die "unknown WAN '$wan' -- add it to WAN_MTU rather than guessing an MTU"
+  cur_src="$(tunnel_src)"; cur_mtu="$(tunnel_mtu)"
+
+  if [ "$cur_src" = "$src" ] && [ "$cur_mtu" = "$want_mtu" ]; then
+    rm -f "$STATE"
+    log "in sync: $TUNNEL via $wan src $src mtu $cur_mtu"
+    return 0
+  fi
+
+  # Hysteresis: count consecutive runs agreeing on the same target.
+  local seen=0 last=""
+  [ -r "$STATE" ] && { read -r last seen < "$STATE"; }
+  if [ "$last" = "$src" ]; then seen=$((seen + 1)); else seen=1; fi
+  echo "$src $seen" > "$STATE"
+  if [ "$seen" -lt "$HYSTERESIS" ]; then
+    log "change seen ($cur_src -> $src) but waiting for stability ($seen/$HYSTERESIS)"
+    return 0
+  fi
+
+  if [ "$dry" = "--dry" ]; then
+    log "DRY RUN: would set HE endpoint to $src, then $TUNNEL local $src mtu $want_mtu"
+    return 0
+  fi
+
+  # HE first, then local. Either order costs a brief drop, but changing locally
+  # first guarantees HE discards our packets for the whole window.
+  he_update "$src" || return 1
+  sudo ip tunnel change "$TUNNEL" mode sit local "$src" || die "failed to set tunnel local address"
+  sudo ip link set "$TUNNEL" mtu "$want_mtu"            || die "failed to set tunnel MTU"
+  rm -f "$STATE"
+  log "moved $TUNNEL to $wan: src $cur_src -> $src, mtu $cur_mtu -> $want_mtu"
+}
+
+case "${1:-status}" in
+  status)
+    wan="$(active_wan)"
+    printf '  active WAN : %s\n' "${wan:-<none>}"
+    printf '  wan addr   : %s\n' "$(addr_of "${wan:-lo}")"
+    printf '  tunnel src : %s\n' "$(tunnel_src)"
+    printf '  tunnel mtu : %s (want %s)\n' "$(tunnel_mtu)" "${WAN_MTU[${wan:-}]:-?}"
+    [ -r "$SECRETS" ] && printf '  credentials: present\n' || printf '  credentials: MISSING (%s)\n' "$SECRETS"
+    ;;
+  run) reconcile "${2:-}" ;;
+  *)   die "usage: he-tunnel-follow {status|run [--dry]}" ;;
+esac

migration/unifi-export.py

@@ -0,0 +1,335 @@
+#!/usr/bin/env python3
+"""Export everything from the UniFi controller that the VyOS cutover must preserve.
+
+The point is that nothing quietly stops working after the switch. That means
+capturing not just the networks but every DHCP reservation, every port forward
+and every firewall rule — the things nobody remembers configuring until they
+break.
+
+Writes one JSON file per endpoint into ./export/ (raw, unmodified — the source
+of truth) plus inventory.json, a normalised view used by the VyOS generator.
+
+  ./unifi-export.py                 # export to ./export/
+  ./unifi-export.py --out /tmp/x    # elsewhere
+  ./unifi-export.py --summary       # print a human summary of what was found
+
+WARNING: the raw export contains secrets (wlanconf holds WiFi passphrases,
+setting holds RADIUS/auth material). ./export/ is gitignored — keep it that way.
+"""
+from __future__ import annotations
+
+import argparse
+import ipaddress
+import json
+import os
+import sys
+
+import _unifi
+
+# endpoint -> why it matters for the cutover
+ENDPOINTS = {
+    "rest/networkconf": "networks: VLANs, subnets, DHCP ranges, DNS, lease time",
+    "rest/user":        "known clients — this is where fixed DHCP reservations live",
+    "stat/sta":         "currently active clients and their live IPs",
+    "rest/firewallrule": "firewall rules",
+    "rest/firewallgroup": "address/port groups referenced by rules",
+    "rest/portforward": "port forwards (inbound NAT)",
+    "rest/routing":     "static routes",
+    "rest/dhcpoption":  "custom DHCP options",
+    "rest/wlanconf":    "wireless networks (VLAN bindings)",
+    "stat/device":      "switches/APs incl. per-port VLAN config",
+    "rest/setting":     "controller settings (incl. USG/gateway config)",
+    "rest/usergroup":   "bandwidth groups referenced by clients",
+    "rest/dynamicdns":  "dynamic DNS",
+}
+
+
+def build_inventory(raw: dict) -> dict:
+    """Normalise the parts a migration actually has to reproduce."""
+    nets_by_id = {n["_id"]: n for n in raw.get("rest/networkconf", []) if isinstance(n, dict)}
+
+    networks = []
+    for n in raw.get("rest/networkconf", []):
+        if not isinstance(n, dict):
+            continue
+        networks.append({
+            "id": n.get("_id"),
+            "name": n.get("name"),
+            "purpose": n.get("purpose"),
+            "vlan": n.get("vlan"),
+            "vlan_enabled": n.get("vlan_enabled"),
+            "subnet": n.get("ip_subnet"),
+            "domain_name": n.get("domain_name"),
+            "dhcp_enabled": n.get("dhcpd_enabled"),
+            "dhcp_start": n.get("dhcpd_start"),
+            "dhcp_stop": n.get("dhcpd_stop"),
+            "dhcp_lease": n.get("dhcpd_leasetime"),
+            "dhcp_dns": [n.get(f"dhcpd_dns_{i}") for i in (1, 2, 3, 4) if n.get(f"dhcpd_dns_{i}")],
+            "dhcp_gateway": n.get("dhcpd_gateway") or n.get("dhcpd_gateway_enabled"),
+            "dhcp_ntp": [n.get(f"dhcpd_ntp_{i}") for i in (1, 2) if n.get(f"dhcpd_ntp_{i}")],
+            "igmp_snooping": n.get("igmp_snooping"),
+            "enabled": n.get("enabled", True),
+        })
+
+    # ip_subnet is the GATEWAY address with a prefix ("10.0.0.1/23"), not the
+    # network address — so derive the real subnet before matching against it.
+    subnets = []
+    for n in networks:
+        if not n["subnet"]:
+            continue
+        try:
+            iface = ipaddress.ip_interface(n["subnet"])
+        except ValueError:
+            continue
+        subnets.append((iface.network, n))
+
+    def resolve_net(ip: str | None, network_id: str | None) -> dict:
+        """Which network does this reservation belong to?
+
+        Most reservations here (23 of 31 as of the first export) carry no
+        network_id at all — UniFi simply does not bind them. VyOS needs the
+        subnet to place a static-mapping, so fall back to containment.
+        """
+        if network_id and network_id in nets_by_id:
+            nid = nets_by_id[network_id]
+            return {"name": nid.get("name"), "vlan": nid.get("vlan"), "by": "network_id"}
+        if ip:
+            try:
+                addr = ipaddress.ip_address(ip)
+            except ValueError:
+                return {"name": None, "vlan": None, "by": "unresolved"}
+            for net, meta in subnets:
+                if addr in net:
+                    return {"name": meta["name"], "vlan": meta["vlan"], "by": "subnet"}
+        return {"name": None, "vlan": None, "by": "unresolved"}
+
+    # Fixed reservations: the single most important thing to carry over, and
+    # the easiest to lose — nobody has these written down anywhere else.
+    reservations = []
+    for u in raw.get("rest/user", []):
+        if not isinstance(u, dict) or not u.get("use_fixedip"):
+            continue
+        net = resolve_net(u.get("fixed_ip"), u.get("network_id"))
+        reservations.append({
+            "mac": (u.get("mac") or "").lower(),
+            "ip": u.get("fixed_ip"),
+            "name": u.get("name") or u.get("hostname") or "",
+            "hostname": u.get("hostname") or "",
+            "network_id": u.get("network_id"),
+            "network_name": net["name"],
+            "network_vlan": net["vlan"],
+            "resolved_by": net["by"],
+            "note": (u.get("note") or "").strip(),
+        })
+    reservations.sort(key=lambda r: tuple(int(p) for p in r["ip"].split(".")) if r["ip"] else (0,))
+
+    # Active leases without a reservation: these devices work today by luck of
+    # the lease database. After a DHCP server swap they get a NEW address.
+    reserved_macs = {r["mac"] for r in reservations}
+    dynamic = []
+    for c in raw.get("stat/sta", []):
+        if not isinstance(c, dict):
+            continue
+        mac = (c.get("mac") or "").lower()
+        if mac in reserved_macs or not c.get("ip"):
+            continue
+        dynamic.append({
+            "mac": mac,
+            "ip": c.get("ip"),
+            "name": c.get("name") or c.get("hostname") or "",
+            "network": c.get("network"),
+        })
+    dynamic.sort(key=lambda r: tuple(int(p) for p in r["ip"].split(".")) if r["ip"] else (0,))
+
+    port_forwards = [{
+        "name": p.get("name"), "enabled": p.get("enabled"),
+        "proto": p.get("proto"), "src": p.get("src"),
+        "dst_port": p.get("dst_port"), "fwd": p.get("fwd"),
+        "fwd_port": p.get("fwd_port"), "log": p.get("log"),
+    } for p in raw.get("rest/portforward", []) if isinstance(p, dict)]
+
+    firewall_rules = [{
+        "name": r.get("name"), "enabled": r.get("enabled"), "action": r.get("action"),
+        "ruleset": r.get("ruleset"), "rule_index": r.get("rule_index"),
+        "protocol": r.get("protocol"),
+        "src_address": r.get("src_address"), "dst_address": r.get("dst_address"),
+        "src_firewallgroup_ids": r.get("src_firewallgroup_ids"),
+        "dst_firewallgroup_ids": r.get("dst_firewallgroup_ids"),
+        "src_networkconf_id": r.get("src_networkconf_id"),
+        "dst_networkconf_id": r.get("dst_networkconf_id"),
+    } for r in raw.get("rest/firewallrule", []) if isinstance(r, dict)]
+
+    firewall_groups = [{
+        "id": g.get("_id"), "name": g.get("name"),
+        "type": g.get("group_type"), "members": g.get("group_members"),
+    } for g in raw.get("rest/firewallgroup", []) if isinstance(g, dict)]
+
+    static_routes = [{
+        "name": r.get("name"), "enabled": r.get("enabled"),
+        "network": r.get("static-route_network"),
+        "nexthop": r.get("static-route_nexthop"),
+        "distance": r.get("static-route_distance"),
+        "type": r.get("static-route_type"),
+    } for r in raw.get("rest/routing", []) if isinstance(r, dict)]
+
+    return {
+        "networks": networks,
+        "reservations": reservations,
+        "dynamic_clients": dynamic,
+        "port_forwards": port_forwards,
+        "firewall_rules": firewall_rules,
+        "firewall_groups": firewall_groups,
+        "static_routes": static_routes,
+        "warnings": find_warnings(networks, reservations),
+    }
+
+
+def find_warnings(networks: list, reservations: list) -> list:
+    """Things that are fine under UniFi but bite when rebuilt on VyOS."""
+    warns = []
+
+    for n in networks:
+        if not n["subnet"]:
+            continue
+        try:
+            iface = ipaddress.ip_interface(n["subnet"])
+        except ValueError:
+            warns.append({"kind": "bad_subnet", "network": n["name"], "detail": n["subnet"]})
+            continue
+        # UniFi stores the gateway in ip_subnet. A gateway equal to the network
+        # address is legal in a /23 but plenty of tooling rejects it, so it must
+        # not be discovered during the cutover window.
+        if iface.ip == iface.network.network_address:
+            warns.append({
+                "kind": "gateway_is_network_address", "network": n["name"],
+                "detail": f"gateway {iface.ip} is the network address of {iface.network}",
+            })
+
+    # Reservations that sit inside the dynamic pool. UniFi's dhcpd tolerates
+    # this; whether VyOS does depends on its DHCP backend, so every one of these
+    # is a config that must be proven on the sim before cutover.
+    ranges = []
+    for n in networks:
+        if n["dhcp_enabled"] and n["dhcp_start"] and n["dhcp_stop"]:
+            try:
+                ranges.append((n["name"], ipaddress.ip_address(n["dhcp_start"]),
+                               ipaddress.ip_address(n["dhcp_stop"])))
+            except ValueError:
+                pass
+    inside = []
+    for r in reservations:
+        if not r["ip"]:
+            continue
+        try:
+            addr = ipaddress.ip_address(r["ip"])
+        except ValueError:
+            continue
+        for name, lo, hi in ranges:
+            if lo <= addr <= hi:
+                inside.append(f"{r['ip']} ({r['name'] or r['mac']}) in {name} pool")
+                break
+    if inside:
+        warns.append({"kind": "reservation_inside_dhcp_pool",
+                      "count": len(inside), "detail": inside})
+
+    unresolved = [f"{r['ip']} {r['mac']} {r['name']}"
+                  for r in reservations if r["resolved_by"] == "unresolved"]
+    if unresolved:
+        warns.append({"kind": "reservation_matches_no_subnet",
+                      "count": len(unresolved), "detail": unresolved})
+    return warns
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--out", default=os.path.join(os.path.dirname(os.path.abspath(__file__)), "export"))
+    ap.add_argument("--summary", action="store_true")
+    args = ap.parse_args()
+
+    os.makedirs(args.out, exist_ok=True)
+    opener, base, site = _unifi.client()
+    print(f"controller {base}  site {site}")
+
+    raw: dict = {}
+    errors = []
+    for path, why in ENDPOINTS.items():
+        data = _unifi.get(opener, base, site, path)
+        if isinstance(data, dict) and "__error__" in data:
+            errors.append((path, data["__error__"]))
+            print(f"  {path:22} FAILED  {data['__error__'][:50]}")
+            continue
+        raw[path] = data
+        fname = path.replace("/", "_") + ".json"
+        with open(os.path.join(args.out, fname), "w") as fh:
+            json.dump(data, fh, indent=2, sort_keys=True)
+        print(f"  {path:22} {len(data):4d}  -> {fname}")
+
+    inventory = build_inventory(raw)
+    with open(os.path.join(args.out, "inventory.json"), "w") as fh:
+        json.dump(inventory, fh, indent=2, sort_keys=True)
+
+    print(f"\nwrote {args.out}/inventory.json")
+    print(f"  networks           {len(inventory['networks'])}")
+    print(f"  DHCP reservations  {len(inventory['reservations'])}")
+    print(f"  dynamic clients    {len(inventory['dynamic_clients'])}  (no reservation — see summary)")
+    print(f"  port forwards      {len(inventory['port_forwards'])}")
+    print(f"  firewall rules     {len(inventory['firewall_rules'])}")
+    print(f"  static routes      {len(inventory['static_routes'])}")
+    if errors:
+        print(f"  endpoints failed   {len(errors)}: {[e[0] for e in errors]}")
+
+    if args.summary:
+        print_summary(inventory)
+    return 0
+
+
+def print_summary(inv: dict) -> None:
+    print("\n=== networks ===")
+    print(f"{'name':22} {'vlan':>5}  {'subnet':20} {'dhcp range':32} lease")
+    for n in sorted(inv["networks"], key=lambda x: (x["vlan"] or 0)):
+        rng = f"{n['dhcp_start']} - {n['dhcp_stop']}" if n["dhcp_enabled"] else "(dhcp off)"
+        print(f"{(n['name'] or '')[:22]:22} {str(n['vlan'] or '-'):>5}  "
+              f"{(n['subnet'] or '-'):20} {rng:32} {n['dhcp_lease'] or '-'}")
+
+    print(f"\n=== DHCP reservations ({len(inv['reservations'])}) ===")
+    for r in inv["reservations"]:
+        print(f"  {r['ip']:16} {r['mac']:18} {(r['network_name'] or '?')[:14]:14} {r['name'][:30]}")
+
+    if inv["port_forwards"]:
+        print(f"\n=== port forwards ({len(inv['port_forwards'])}) ===")
+        for p in inv["port_forwards"]:
+            state = "" if p["enabled"] else "  [DISABLED]"
+            print(f"  {p['proto']:6} {str(p['src']):16}:{str(p['dst_port']):11} -> "
+                  f"{p['fwd']}:{p['fwd_port']}   {p['name']}{state}")
+
+    if inv["firewall_rules"]:
+        print(f"\n=== firewall rules ({len(inv['firewall_rules'])}) ===")
+        for r in inv["firewall_rules"]:
+            state = "" if r["enabled"] else "  [DISABLED]"
+            print(f"  {str(r['ruleset']):22} {str(r['action']):8} {r['name']}{state}")
+
+    if inv["warnings"]:
+        print(f"\n=== {len(inv['warnings'])} things to settle before cutover ===")
+        for w in inv["warnings"]:
+            n = w.get("count")
+            print(f"  [{w['kind']}]" + (f"  x{n}" if n else ""))
+            det = w["detail"]
+            for line in (det if isinstance(det, list) else [det])[:6]:
+                print(f"      {line}")
+            if isinstance(det, list) and len(det) > 6:
+                print(f"      ... and {len(det) - 6} more (see inventory.json)")
+
+    n_dyn = len(inv["dynamic_clients"])
+    if n_dyn:
+        print(f"\n=== {n_dyn} active clients WITHOUT a reservation ===")
+        print("  These hold their address only via the current lease database. A DHCP")
+        print("  server swap hands them a different one — fine for phones, not fine for")
+        print("  anything another host reaches by IP. Review before cutover:")
+        for c in inv["dynamic_clients"][:40]:
+            print(f"  {c['ip']:16} {c['mac']:18} {(c['network'] or '')[:14]:14} {c['name'][:30]}")
+        if n_dyn > 40:
+            print(f"  ... and {n_dyn - 40} more (see inventory.json)")
+
+
+if __name__ == "__main__":
+    sys.exit(main())

migration/unifi-reserve-all.py

@@ -0,0 +1,236 @@
+#!/usr/bin/env python3
+"""Reserve every active client at the address it already has.
+
+Why this exists: kea does not inherit UniFi's lease database. At cutover it
+starts with an empty view of who holds what, so it can hand an address that is
+currently in use to a different device. Reservations are what carry "this
+device has this address" across the switch, because they live in config rather
+than in lease state.
+
+Dry run by default -- this writes to the live controller, and 40-odd writes is
+not something to trigger by accident.
+
+  ./unifi-reserve-all.py                  # show the plan, change nothing
+  ./unifi-reserve-all.py --apply          # write them
+  ./unifi-reserve-all.py --skip-random    # omit randomised/private MACs
+
+Only clients on networks that actually run DHCP are considered, which
+automatically excludes WAN transit VLANs where a reservation is meaningless.
+Anything already reserved is left alone, and an address already reserved to a
+different MAC is reported and skipped rather than stolen.
+"""
+from __future__ import annotations
+
+import argparse
+import ipaddress
+import sys
+
+import _unifi
+
+# The VRRP virtual addresses, read from `show configuration commands` on
+# vyos001. UniFi sees these as ordinary client addresses because the firewalls'
+# bond MACs answer for them, and their reported IP flips between the real
+# interface address and the VIP. Reserving one would put a DHCP reservation on
+# the gateway address itself.
+VIPS = {
+    "192.168.1.254", "192.168.9.254", "192.168.3.254",
+    "10.0.9.254", "10.0.1.254", "192.168.2.254",
+}
+
+# Every MAC the two firewalls own (bond0/eth0/eth1 share one, eth2 and eth3
+# have their own). These interfaces are statically configured routers, not DHCP
+# clients -- except eth2, which is deliberately reserved and already handled.
+ROUTER_MACS = {
+    "64:62:66:25:96:45", "64:62:66:25:96:46", "64:62:66:25:96:48",  # vyos001
+    "64:62:66:25:96:51", "64:62:66:25:96:52", "64:62:66:25:96:54",  # vyos002
+}
+
+
+def is_random_mac(mac: str) -> bool:
+    """Locally-administered bit set => a privacy/randomised MAC.
+
+    Worth calling out: such a device re-randomises periodically, so the
+    reservation stops matching it and becomes dead config. Harmless, but it
+    will never do what it looks like it does.
+    """
+    try:
+        return bool(int(mac.split(":")[0], 16) & 0x02)
+    except (ValueError, IndexError):
+        return False
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--apply", action="store_true", help="actually write (default: dry run)")
+    ap.add_argument("--skip-random", action="store_true", help="omit randomised MACs")
+    ap.add_argument("--plan", default="reservation-plan.tsv",
+                    help="dry run WRITES this file; --apply READS it and applies "
+                         "exactly what it contains")
+    args = ap.parse_args()
+
+    opener, base, site = _unifi.client()
+    users = _unifi.get(opener, base, site, "rest/user")
+    nets = _unifi.get(opener, base, site, "rest/networkconf")
+    sta = _unifi.get(opener, base, site, "stat/sta")
+    for blob in (users, nets, sta):
+        if isinstance(blob, dict):
+            print(f"error reading controller: {blob['__error__']}", file=sys.stderr)
+            return 1
+
+    # Only networks that serve DHCP: a reservation on a WAN transit VLAN means
+    # nothing, and those are exactly the ones without dhcpd_enabled.
+    serving = []
+    for n in nets:
+        if not (n.get("dhcpd_enabled") and n.get("ip_subnet")):
+            continue
+        try:
+            serving.append((ipaddress.ip_interface(n["ip_subnet"]).network, n))
+        except ValueError:
+            continue
+
+    by_mac = {(u.get("mac") or "").lower(): u for u in users}
+    taken = {u.get("fixed_ip"): (u.get("mac") or "").lower()
+             for u in users if u.get("use_fixedip")}
+
+    plan, skipped = [], []
+    for c in sta:
+        mac, ip = (c.get("mac") or "").lower(), c.get("ip")
+        if not mac or not ip:
+            continue
+        label = c.get("name") or c.get("hostname") or "?"
+        user = by_mac.get(mac)
+
+        if ip in VIPS:
+            skipped.append((ip, mac, label, "VRRP virtual address - not a client"))
+            continue
+        if mac in ROUTER_MACS:
+            skipped.append((ip, mac, label, "firewall's own interface - statically configured"))
+            continue
+
+        net = next((n for netw, n in serving if ipaddress.ip_address(ip) in netw), None)
+        if net is None:
+            skipped.append((ip, mac, label, "not on a DHCP-serving network"))
+            continue
+        # The gateway is the router, not a lease.
+        if ip == str(ipaddress.ip_interface(net["ip_subnet"]).ip):
+            skipped.append((ip, mac, label, "network gateway address"))
+            continue
+        if user is None:
+            skipped.append((ip, mac, label, "not a known client on the controller"))
+            continue
+        if user.get("use_fixedip"):
+            if user.get("fixed_ip") != ip:
+                skipped.append((ip, mac, label,
+                                f"already reserved at {user.get('fixed_ip')} - left alone"))
+            continue
+        if ip in taken and taken[ip] != mac:
+            skipped.append((ip, mac, label,
+                            f"address already reserved to {taken[ip]}"))
+            continue
+        if args.skip_random and is_random_mac(mac):
+            skipped.append((ip, mac, label, "randomised MAC (--skip-random)"))
+            continue
+        plan.append((ip, mac, label, user, net))
+
+    # Generic safety net: if two MACs report the same current address, at most
+    # one of them can legitimately keep it and we cannot tell which. Drop both
+    # and say so -- this is exactly how the VRRP VIPs first showed up.
+    counts: dict[str, int] = {}
+    for ip, *_ in plan:
+        counts[ip] = counts.get(ip, 0) + 1
+    contested = {ip for ip, n in counts.items() if n > 1}
+    if contested:
+        for ip, mac, label, _u, _n in [p for p in plan if p[0] in contested]:
+            skipped.append((ip, mac, label, "address claimed by more than one MAC"))
+        plan = [p for p in plan if p[0] not in contested]
+
+    plan.sort(key=lambda r: ipaddress.ip_address(r[0]))
+
+    print(f"=== plan: {len(plan)} new reservation(s) ===")
+    for ip, mac, label, _u, net in plan:
+        flag = "  [randomised MAC]" if is_random_mac(mac) else ""
+        print(f"  {ip:16} {mac:18} {label[:28]:28} {net.get('name')}{flag}")
+    if skipped:
+        print(f"\n=== skipped ({len(skipped)}) ===")
+        for ip, mac, label, why in sorted(skipped):
+            print(f"  {ip:16} {mac:18} {label[:24]:24} {why}")
+
+    n_rand = sum(1 for p in plan if is_random_mac(p[1]))
+    if n_rand:
+        print(f"\nnote: {n_rand} of these use randomised MACs. The reservation "
+              f"stops matching once the device re-randomises.")
+
+    if not args.apply:
+        with open(args.plan, "w") as fh:
+            for ip, mac, label, _u, _n in plan:
+                fh.write(f"{mac}\t{ip}\t{label}\n")
+        print(f"\ndry run -- nothing written to the controller.")
+        print(f"plan saved to {args.plan}; re-run with --apply to apply exactly that.")
+        return 0
+
+    # Apply the plan that was REVIEWED, not one recomputed now.
+    #
+    # This cost a k8s node an outage. The apply used to re-read stat/sta, and a
+    # client that renewed between the dry run and the apply got pinned to
+    # whatever transient address it happened to hold at that instant -- worker1
+    # was reviewed at .13 and written as .242. A plan you looked at and a plan
+    # that gets applied must be the same object.
+    try:
+        with open(args.plan) as fh:
+            reviewed = {}
+            for line in fh:
+                parts = line.rstrip("\n").split("\t")
+                if len(parts) >= 2:
+                    reviewed[parts[0].lower()] = parts[1]
+    except OSError:
+        print(f"no plan at {args.plan}. Run without --apply first and review it.",
+              file=sys.stderr)
+        return 1
+
+    drifted = [(ip, mac) for ip, mac, _l, _u, _n in plan
+               if mac in reviewed and reviewed[mac] != ip]
+    for ip, mac in drifted:
+        print(f"  note: {mac} now reports {ip}, plan says {reviewed[mac]} -- "
+              f"applying the plan", file=sys.stderr)
+
+    plan = [(reviewed[mac], mac, label, user, net)
+            for ip, mac, label, user, net in plan if mac in reviewed]
+    print(f"applying {len(plan)} reservation(s) from {args.plan}")
+
+    print()
+    ok = fail = 0
+    for ip, mac, label, user, net in plan:
+        res = _unifi.put(opener, base, site, f"rest/user/{user['_id']}",
+                         {"use_fixedip": True, "fixed_ip": ip, "network_id": net["_id"]})
+        if isinstance(res, dict):
+            print(f"  FAILED {ip:16} {mac}  {res['__error__'][:70]}")
+            fail += 1
+        else:
+            ok += 1
+
+    # Read back rather than trusting the write responses.
+    after = _unifi.get(opener, base, site, "rest/user")
+    live = {(u.get("mac") or "").lower() for u in after if u.get("use_fixedip")}
+    verified = sum(1 for _ip, mac, _l, _u, _n in plan if mac in live)
+    print(f"\nwrote {ok}, failed {fail}, verified live {verified}/{len(plan)}")
+    print(f"total reservations on the controller now: "
+          f"{sum(1 for u in after if u.get('use_fixedip'))}")
+
+    # Writing the controller is only half the job. The gateway applies config
+    # on its own schedule, and a device running config from before these
+    # changes will hand out addresses that disagree with what the controller
+    # shows -- which is how a k8s node ended up unable to get any lease at all
+    # while the controller looked perfectly correct.
+    print("\nThe controller now disagrees with what the gateway is running.")
+    print("Push it to the device and wait for state to return to 'connected':")
+    print("  python3 -c \"import _unifi; o,b,s=_unifi.client(); "
+          "print(_unifi.post(o,b,s,'cmd/devmgr',"
+          "{'cmd':'force-provision','mac':'<gateway-mac>'}))\"")
+    print("Then verify a real DISCOVER is answered before trusting it:")
+    print("  ssh vyos@<fw> 'sudo nmap --script broadcast-dhcp-discover -e eth2 "
+          "--script-args broadcast-dhcp-discover.mac=<client-mac>'")
+    return 0 if fail == 0 and verified == len(plan) else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())

migration/unifi-reserve.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""Set a fixed-IP reservation in UniFi, so it cannot lease that address away.
+
+Written for the firewalls' management NICs: their addresses are pinned static
+on the VyOS side, but UniFi still owns the pool they sit in and would happily
+hand the same address to something else. A reservation closes that gap while
+the USG is still the DHCP server, and it keeps the management address identical
+in both cutover modes.
+
+  ./unifi-reserve.py 64:62:66:25:96:47 192.168.8.143
+  ./unifi-reserve.py --dry-run <mac> <ip>
+
+Idempotent: an existing, matching reservation is reported and left alone. This
+writes to the live controller, so it verifies by reading the record back rather
+than trusting the response.
+"""
+from __future__ import annotations
+
+import argparse
+import ipaddress
+import sys
+
+import _unifi
+
+
+def find_network(nets: list, ip: str) -> dict | None:
+    """Which configured network contains this address?
+
+    ip_subnet holds the gateway address with a prefix ("192.168.8.1/23"), so
+    the network has to be derived from it rather than compared directly.
+    """
+    addr = ipaddress.ip_address(ip)
+    for n in nets:
+        raw = n.get("ip_subnet")
+        if not raw:
+            continue
+        try:
+            if addr in ipaddress.ip_interface(raw).network:
+                return n
+        except ValueError:
+            continue
+    return None
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("mac")
+    ap.add_argument("ip")
+    ap.add_argument("--dry-run", action="store_true")
+    args = ap.parse_args()
+
+    mac = args.mac.lower().replace("-", ":")
+    ipaddress.ip_address(args.ip)  # fail early on a typo
+
+    opener, base, site = _unifi.client()
+    users = _unifi.get(opener, base, site, "rest/user")
+    nets = _unifi.get(opener, base, site, "rest/networkconf")
+    for blob in (users, nets):
+        if isinstance(blob, dict):
+            print(f"error reading controller: {blob['__error__']}", file=sys.stderr)
+            return 1
+
+    user = next((u for u in users if (u.get("mac") or "").lower() == mac), None)
+    if user is None:
+        print(f"{mac} is not a known client -- connect it once, or create it "
+              f"in the UI first", file=sys.stderr)
+        return 1
+
+    net = find_network(nets, args.ip)
+    if net is None:
+        print(f"no configured network contains {args.ip}", file=sys.stderr)
+        return 1
+
+    label = user.get("name") or user.get("hostname") or mac
+    if user.get("use_fixedip") and user.get("fixed_ip") == args.ip:
+        print(f"{label} ({mac}) already reserved at {args.ip} -- nothing to do")
+        return 0
+    if user.get("use_fixedip"):
+        print(f"WARNING: {label} currently reserved at {user.get('fixed_ip')}, "
+              f"changing to {args.ip}", file=sys.stderr)
+
+    print(f"{label} ({mac}) -> {args.ip} on '{net.get('name')}' (VLAN {net.get('vlan') or 'native'})")
+    if args.dry_run:
+        print("  --dry-run: not writing")
+        return 0
+
+    payload = {"use_fixedip": True, "fixed_ip": args.ip, "network_id": net["_id"]}
+    res = _unifi.put(opener, base, site, f"rest/user/{user['_id']}", payload)
+    if isinstance(res, dict):
+        print(f"  write failed: {res['__error__']}", file=sys.stderr)
+        return 1
+
+    # Read it back: the controller accepting a PUT is not proof it stored what
+    # we asked for.
+    after = _unifi.get(opener, base, site, "rest/user")
+    check = next((u for u in after if (u.get("mac") or "").lower() == mac), {})
+    if check.get("use_fixedip") and check.get("fixed_ip") == args.ip:
+        print(f"  verified: reservation is live")
+        return 0
+    print(f"  VERIFY FAILED: controller reports use_fixedip="
+          f"{check.get('use_fixedip')} fixed_ip={check.get('fixed_ip')}", file=sys.stderr)
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())

migration/unifi-to-vyos.py

@@ -0,0 +1,251 @@
+#!/usr/bin/env python3
+"""Turn the UniFi export into the VyOS config that replaces it.
+
+Scope is deliberately narrow: DHCP and DNS. Those are the services the USG owns
+that VyOS must reproduce byte-for-byte in behaviour, because getting them wrong
+means clients lose their addresses or their name resolution. Everything else
+either stays on UniFi (wireless), has no VyOS equivalent (user groups), or is
+hand-written because it is not in the export (WAN, NAT, VRRP).
+
+This is not a general UniFi-to-VyOS converter and should not grow into one.
+
+  ./unifi-to-vyos.py --mode prod          # the cutover artifact
+  ./unifi-to-vyos.py --mode sim           # same MACs, labsim addresses
+  ./unifi-to-vyos.py --mode prod --check  # counts only, no output
+
+Both modes come from one code path on purpose: the config proven in labsim and
+the config applied to the firewalls must not be able to drift apart.
+
+DNS note: UniFi hands out the gateway's own IP as resolver whenever a network
+has no explicit dhcpd_dns -- true for 5 of the 6 VLANs, verified by labmaster
+resolving against 192.168.8.1. So VyOS must run `service dns forwarding` or
+those VLANs lose DNS entirely at cutover. LoT's explicit 10.0.0.194 is preserved
+as-is.
+"""
+from __future__ import annotations
+
+import argparse
+import ipaddress
+import json
+import os
+import re
+import sys
+
+# Upstream resolvers for VyOS's own forwarder -- the same pair the USG used on
+# its WAN (wan_dns1/wan_dns2). The NAS at 10.0.0.194 is deliberately NOT here:
+# it is legacy for ad.itaz.eu, and those records now live in Cloudflare, so the
+# zone resolves publicly (verified: nas001.ad.itaz.eu and kvm-macstudio1 both
+# answer from 8.8.8.8). That means no conditional forward is needed and the NAS
+# is out of the DNS path entirely.
+UPSTREAM_DNS = ["8.8.8.8", "8.8.4.4"]
+
+# labsim equivalents, keyed by VLAN id. Only VLAN 10 needs a /23: every one of
+# the 31 reservations is in LoT, which spans 10.0.0.x and 10.0.1.x, and a /24
+# cannot represent that. k8s and Private are also /23 in production but hold no
+# reservations, so they keep their existing /24 and their DHCP range is clamped
+# (reported at generation time -- never silently).
+SIM_SUBNETS = {
+    1:   "172.31.1.0/24",
+    2:   "172.31.2.0/24",
+    3:   "172.31.3.0/24",
+    9:   "172.31.9.0/24",
+    10:  "172.31.10.0/23",
+    200: "172.31.200.0/24",
+}
+
+
+def vlan_of(net: dict) -> int:
+    """VLAN id, treating the untagged Management network as 1.
+
+    UniFi stores vlan=None for the native network; the VyOS side already uses
+    vrid 1 for it (high-availability group 'native'), so 1 is the consistent id.
+    """
+    return int(net["vlan"]) if net.get("vlan") else 1
+
+
+def sanitize(name: str, fallback: str) -> str:
+    """Reduce a UniFi client name to something VyOS will accept as a node name.
+
+    VyOS validates static-mapping names as *hostnames*, so underscores are
+    rejected outright -- verified: `Dongle-M_C0D4` fails with "Invalid static
+    mapping hostname". Letters, digits and hyphens only, no leading digit or
+    hyphen, no trailing hyphen.
+    """
+    cleaned = re.sub(r"[^A-Za-z0-9-]", "-", (name or "").strip())
+    cleaned = re.sub(r"-{2,}", "-", cleaned).strip("-")
+    if cleaned and cleaned[0].isdigit():
+        cleaned = "h" + cleaned
+    return cleaned or fallback
+
+
+class Mapper:
+    """Translates production addresses into the target mode's address space.
+
+    In prod mode this is the identity. In sim mode an address is mapped by its
+    offset from the network address, so the host part is preserved: 10.0.0.46
+    -> 172.31.10.46 and 10.0.1.67 -> 172.31.11.67. That is what makes the sim
+    test meaningful -- the MAC is identical and the host octet is recognisable.
+    """
+
+    def __init__(self, mode: str, networks: list) -> None:
+        self.mode = mode
+        self.clamped: list[str] = []
+        self.map: dict[int, tuple] = {}
+        for n in networks:
+            prod = ipaddress.ip_network(
+                ipaddress.ip_interface(n["subnet"]).network)
+            if mode == "sim":
+                sim = ipaddress.ip_network(SIM_SUBNETS[vlan_of(n)])
+            else:
+                sim = prod
+            self.map[vlan_of(n)] = (prod, sim)
+
+    def net(self, vlan: int) -> ipaddress.IPv4Network:
+        return self.map[vlan][1]
+
+    def addr(self, vlan: int, ip: str, what: str) -> str | None:
+        """Map one address, or None if it does not fit the target subnet."""
+        prod, sim = self.map[vlan]
+        offset = int(ipaddress.ip_address(ip)) - int(prod.network_address)
+        if offset < 0 or offset >= sim.num_addresses:
+            self.clamped.append(f"{what}: {ip} does not fit {sim}")
+            return None
+        return str(ipaddress.ip_address(int(sim.network_address) + offset))
+
+    def gateway(self, vlan: int, net: dict) -> str:
+        """The address clients are told to use as their default route.
+
+        Production: the USG's current address (VIPs move .254 -> .1 at cutover),
+        so no client has to change anything. Sim: the sim router at .1.
+        """
+        if self.mode == "sim":
+            return str(self.net(vlan).network_address + 1)
+        return str(ipaddress.ip_interface(net["subnet"]).ip)
+
+
+def build(inv: dict, mode: str) -> tuple[list[str], dict]:
+    nets = [n for n in inv["networks"] if n["dhcp_enabled"] and n["subnet"]]
+    nets.sort(key=vlan_of)
+    m = Mapper(mode, nets)
+
+    out: list[str] = []
+    used_tags: set[str] = set()
+    stats = {"subnets": 0, "mappings": 0, "dropped": []}
+    by_vlan: dict[int, list] = {}
+    for r in inv["reservations"]:
+        if r["network_vlan"] is None and r["network_name"] != "Management":
+            # resolved_by == "unresolved"; cannot place it without a subnet
+            stats["dropped"].append(f"{r['ip']} {r['mac']} (no network)")
+            continue
+        by_vlan.setdefault(r["network_vlan"] or 1, []).append(r)
+
+    out.append("# --- DHCP ---------------------------------------------------")
+    for n in nets:
+        vlan = vlan_of(n)
+        sub = m.net(vlan)
+        base = f"set service dhcp-server shared-network-name {sanitize(n['name'], f'vlan{vlan}')} subnet {sub}"
+        gw = m.gateway(vlan, n)
+
+        out.append("")
+        out.append(f"# {n['name']} (VLAN {vlan}) <- {n['subnet']}")
+        # subnet-id is required by kea and must be stable across regenerations;
+        # the VLAN id is already the unique per-network number in this lab.
+        out.append(f"{base} subnet-id {vlan}")
+        out.append(f"{base} option default-router {gw}")
+
+        # Every VLAN is handed the gateway as its resolver, so all lookups go
+        # through VyOS and out to the upstreams above. UniFi set an explicit
+        # resolver on LoT only (the NAS); that is deliberately not carried over
+        # -- the NAS is legacy and pointing clients at it would keep it in the
+        # path for one VLAN and not the others.
+        out.append(f"{base} option name-server {gw}")
+
+        if n["domain_name"]:
+            out.append(f"{base} option domain-name '{n['domain_name']}'")
+        if n["dhcp_lease"]:
+            out.append(f"{base} lease {n['dhcp_lease']}")
+
+        start = m.addr(vlan, n["dhcp_start"], f"{n['name']} range start")
+        stop = m.addr(vlan, n["dhcp_stop"], f"{n['name']} range stop")
+        if start is None:
+            start = str(sub.network_address + 11)
+        if stop is None:
+            # Clamp to the last usable address rather than dropping the pool.
+            stop = str(sub.broadcast_address - 1)
+        out.append(f"{base} range LAN start {start}")
+        out.append(f"{base} range LAN stop {stop}")
+        stats["subnets"] += 1
+
+        for r in sorted(by_vlan.get(vlan, []), key=lambda x: ipaddress.ip_address(x["ip"])):
+            ip = m.addr(vlan, r["ip"], f"reservation {r['name']}")
+            if ip is None:
+                stats["dropped"].append(f"{r['ip']} {r['mac']} ({r['name']})")
+                continue
+            tag = sanitize(r["name"] or r["hostname"], "host-" + r["mac"].replace(":", ""))
+            # Distinct clients can sanitize to the same name; a collision would
+            # silently overwrite one reservation with another's address.
+            if tag in used_tags:
+                tag = f"{tag}-{r['mac'].replace(':', '')[-4:]}"
+            used_tags.add(tag)
+            out.append(f"{base} static-mapping {tag} mac {r['mac']}")
+            out.append(f"{base} static-mapping {tag} ip-address {ip}")
+            stats["mappings"] += 1
+
+    out.append("")
+    out.append("# --- DNS ----------------------------------------------------")
+    out.append("# The USG resolves for 5 of 6 VLANs today (it hands out its own")
+    out.append("# address when dhcpd_dns is empty). Without this, they lose DNS.")
+    for n in nets:
+        vlan = vlan_of(n)
+        out.append(f"set service dns forwarding listen-address {m.gateway(vlan, n)}")
+        out.append(f"set service dns forwarding allow-from {m.net(vlan)}")
+    for ns in UPSTREAM_DNS:
+        out.append(f"set service dns forwarding name-server {ns}")
+    out.append("set service dns forwarding cache-size 10000")
+
+    stats["clamped"] = m.clamped
+    return out, stats
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    here = os.path.dirname(os.path.abspath(__file__))
+    ap.add_argument("--mode", choices=("prod", "sim"), required=True)
+    ap.add_argument("--inventory", default=os.path.join(here, "export", "inventory.json"))
+    ap.add_argument("-o", "--out")
+    ap.add_argument("--check", action="store_true", help="counts only, no config")
+    args = ap.parse_args()
+
+    with open(args.inventory) as fh:
+        inv = json.load(fh)
+
+    lines, stats = build(inv, args.mode)
+
+    expected = len(inv["reservations"])
+    print(f"mode={args.mode}  subnets={stats['subnets']}  "
+          f"static-mappings={stats['mappings']}/{expected}", file=sys.stderr)
+    for c in stats["clamped"]:
+        print(f"  clamped: {c}", file=sys.stderr)
+    for d in stats["dropped"]:
+        print(f"  DROPPED: {d}", file=sys.stderr)
+
+    if stats["mappings"] != expected and args.mode == "prod":
+        print(f"ERROR: {expected - stats['mappings']} reservation(s) missing from "
+              f"prod output -- every one must survive the cutover", file=sys.stderr)
+        return 1
+
+    if args.check:
+        return 0
+
+    text = "\n".join(lines) + "\n"
+    if args.out:
+        with open(args.out, "w") as fh:
+            fh.write(text)
+        print(f"wrote {args.out}", file=sys.stderr)
+    else:
+        sys.stdout.write(text)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

migration/vyos-known-good

@@ -0,0 +1,120 @@
+#!/bin/vbash
+# Pin a config you have SEEN working, and get back to it with one command.
+#
+# Why this exists when VyOS already has rollback: `rollback 1` returns you to the
+# previous revision, which may itself be broken -- you can walk backwards through
+# several bad commits looking for the one that worked. This pins a state you
+# explicitly confirmed was good, so recovery is one step and does not require
+# remembering how many changes ago things last worked.
+#
+# It is deliberately NOT automatic. A config is only "known good" once a human
+# has used the network and found it working; a script cannot judge that, and a
+# snapshot taken automatically after every commit would faithfully preserve the
+# broken one.
+#
+#   vyos-known-good save      mark the running config as known-good
+#   vyos-known-good status    when it was taken, and how it differs from running
+#   vyos-known-good restore   go back to it (commit-confirmed, so even this is safe)
+#   vyos-known-good diff      what would change if you restored
+#
+# Lives in /config so it survives image upgrades, like vyos-unifi-switch.
+
+# Capture the arguments BEFORE sourcing script-template: sourcing it resets the
+# positional parameters, so $1 is empty by the time the case statement runs and
+# every invocation silently falls through to the usage message.
+ACTION="${1:-status}"
+
+source /opt/vyatta/etc/functions/script-template
+
+GOOD="/config/known-good.boot"
+META="/config/known-good.meta"
+RUNNING="/config/config.boot"
+CONFIRM_MINUTES="${CONFIRM_MINUTES:-5}"
+
+say()  { printf '\033[0;36m[known-good]\033[0m %s\n' "$*"; }
+warn() { printf '\033[1;33m[known-good]\033[0m %s\n' "$*" >&2; }
+die()  { printf '\033[0;31m[known-good]\033[0m %s\n' "$*" >&2; exit 1; }
+
+# The running config on disk is only current if nothing is uncommitted-and-unsaved.
+# Saving a snapshot that does not match what is actually running would be worse
+# than having no snapshot at all -- it would look like a safety net and not be one.
+require_saved() {
+  if ! cli-shell-api sessionChanged >/dev/null 2>&1; then
+    return 0
+  fi
+  die "there are uncommitted changes; commit and save first, or this snapshot would not match reality"
+}
+
+cmd_save() {
+  require_saved
+  [ -r "$RUNNING" ] || die "cannot read $RUNNING"
+  sudo cp "$RUNNING" "$GOOD"
+  # 0660 root:vyattacfg, matching /config/config.boot. 0600 would make the
+  # snapshot unreadable to the vyos user, so `status` and `diff` -- the two you
+  # run while deciding whether to restore -- would silently show nothing.
+  sudo chmod 0660 "$GOOD"; sudo chgrp vyattacfg "$GOOD"
+  sudo chmod 0660 "$META" 2>/dev/null; sudo chgrp vyattacfg "$META" 2>/dev/null
+  {
+    echo "saved_at=$(date -Is)"
+    echo "saved_by=${SUDO_USER:-$USER}"
+    echo "hostname=$(hostname)"
+    echo "lines=$(wc -l < "$RUNNING")"
+  } | sudo tee "$META" >/dev/null
+  say "pinned $(wc -l < "$GOOD") lines as known-good on $(hostname)"
+  say "restore with: /config/vyos-known-good restore"
+}
+
+cmd_status() {
+  [ -r "$GOOD" ] || { warn "no known-good snapshot on $(hostname) -- run 'save' while things work"; return 1; }
+  say "known-good on $(hostname):"
+  sed 's/^/    /' "$META" 2>/dev/null
+  local n
+  n="$(diff <(grep -vE '^\s*$' "$GOOD") <(grep -vE '^\s*$' "$RUNNING") 2>/dev/null | grep -c '^[<>]')"
+  if [ "${n:-0}" -eq 0 ]; then
+    say "running config MATCHES known-good"
+  else
+    warn "running config differs from known-good by $n line(s) -- 'diff' to see them"
+  fi
+}
+
+cmd_diff() {
+  [ -r "$GOOD" ] || die "no known-good snapshot"
+  diff -u "$GOOD" "$RUNNING" | sed -E "s/(password|key|secret)[[:space:]]+\S+/\1 <REDACTED>/I" || true
+}
+
+cmd_restore() {
+  [ -r "$GOOD" ] || die "no known-good snapshot to restore"
+  say "restoring known-good on $(hostname) (taken $(grep -m1 saved_at "$META" 2>/dev/null | cut -d= -f2-))"
+
+  # Commit-confirmed even here. If the known-good snapshot is itself somehow
+  # wrong, or the restore cannot be confirmed because access is still broken,
+  # the router undoes it rather than leaving you worse off. Silence reverts.
+  local script; script="$(mktemp)"
+  {
+    echo 'source /opt/vyatta/etc/functions/script-template'
+    echo 'configure'
+    echo "load $GOOD"
+    printf 'sudo sg vyattacfg "/usr/bin/config-mgmt commit_confirm -y -t=%s"\n' "$CONFIRM_MINUTES"
+    echo 'export IN_COMMIT_CONFIRM=t'
+    echo 'commit'
+    echo 'unset IN_COMMIT_CONFIRM'
+    echo 'exit'
+  } > "$script"
+  vbash "$script"; local rc=$?
+  rm -f "$script"
+
+  [ $rc -eq 0 ] || die "restore failed (rc=$rc) -- nothing was committed"
+  say ""
+  say "RESTORED under a ${CONFIRM_MINUTES} minute timer."
+  say "Check the network NOW. If it works, confirm it:"
+  say "    sudo sg vyattacfg '/usr/bin/config-mgmt confirm'"
+  say "If you do nothing, the router reverts on its own."
+}
+
+case "$ACTION" in
+  save)    cmd_save ;;
+  status)  cmd_status ;;
+  diff)    cmd_diff ;;
+  restore) cmd_restore ;;
+  *) die "usage: vyos-known-good {save|status|diff|restore}" ;;
+esac

migration/vyos-mode-delta.py

@@ -0,0 +1,491 @@
+#!/usr/bin/env python3
+"""Generate the delta that turns a passive VyOS pair into the gateway.
+
+The switch works as: load the known-good `unifi.boot` snapshot, apply this
+delta, commit-confirm. Deriving the gateway mode from base+delta every time
+means there is no inverse to maintain and no drift between two hand-kept
+configs -- the revert is just loading the snapshot again.
+
+  ./vyos-mode-delta.py --priority 200 -o to-vyos.commands     # vyos001 (master)
+  ./vyos-mode-delta.py --priority 100 -o to-vyos.commands     # vyos002 (backup)
+  ./vyos-mode-delta.py --emit-secrets /path/wan-secrets       # credentials, 0600
+
+The PPPoE password is NOT written into the delta. The delta carries the
+placeholder @@WAN_PASSWORD@@ and the switch script substitutes it at apply time
+from /config/wan-secrets, so the generated artifact can be read, diffed and
+copied around without carrying a credential.
+"""
+from __future__ import annotations
+
+import argparse
+import importlib.util
+import ipaddress
+import json
+import os
+import sys
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+
+# unifi-to-vyos.py has hyphens, so it cannot be imported by name. Reuse it
+# rather than duplicating the DHCP/DNS generation -- the whole point is that
+# what labsim proved and what production gets come from one code path.
+_spec = importlib.util.spec_from_file_location(
+    "unifi_to_vyos", os.path.join(HERE, "unifi-to-vyos.py"))
+unifi_to_vyos = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(unifi_to_vyos)
+
+# Two WANs, established by reading the live USG rather than the UniFi fields
+# (which report wan_type=dhcp for both and are simply wrong):
+#
+#   WAN1  Vodafone, PPPoE on the USG's eth0, ~900/700 Mbit. Verified working:
+#         pppoe0 came up with 90.241.226.213 peer 84.65.128.1, MTU 1492.
+#   WAN2  10 gig ISP, plain DHCP on the USG's eth2, public 87.192.101.48/21
+#         gw 87.192.96.1. This is what carries traffic today.
+#
+# Both reach the USG as untagged access ports but are carried across the switch
+# fabric as vlan-only networks 51 and 53, so VyOS picks them up as bond vifs.
+WAN_PPPOE_VIF = "bond0.51"      # Vodafone
+WAN_PPPOE_IF = "pppoe0"
+WAN_DHCP_VIF = "bond0.53"       # 10 gig ISP
+
+# The DHCP lease is bound to the MAC, so cloning the USG's WAN2 MAC is how VyOS
+# keeps 87.192.101.48 instead of negotiating a fresh lease -- or getting none,
+# if the ISP hands out one per line. Only ONE box may carry this at a time.
+WAN_DHCP_MAC = "f0:9f:c2:12:9b:4f"
+
+# Route distances: the 10 gig line wins, Vodafone is failover.
+#
+# The live 10 gig default route is owned by `protocols failover`, so that losing
+# the ISP *without* losing carrier withdraws it instead of black-holing every
+# packet -- a DHCP-installed route never withdraws on a dead upstream.
+#
+# The vif still needs default-route-distance rather than no-default-route:
+# vyos-failover resolves a dhcp-interface gateway by reading new_routers out of
+# /run/dhclient/dhclient_<if>.lease, and no-default-route leaves that field
+# EMPTY, so the daemon finds no next hop and installs nothing. Verified on
+# vyos001: with no-default-route the default route fell through to Vodafone.
+#
+# So DHCP keeps a route, deliberately demoted BELOW Vodafone. Order of
+# preference: failover's kernel route (distance 0) > pppoe (10) > DHCP (210).
+# The demoted route is never selected while pppoe is up, so it cannot re-create
+# the black-hole it exists to avoid.
+DIST_PPPOE = 10
+DIST_DHCP_FALLBACK = 210
+
+# Health-checked primary. Two targets, any-available, so one resolver having a
+# bad day is not read as "the line is down". Verified on the sim: failover and
+# failback both inside 5s with the router's own interface still UP.
+FAILOVER_METRIC = 1
+FAILOVER_TARGETS = ["8.8.8.8", "1.1.1.1"]
+FAILOVER_TIMEOUT = 5
+
+PLACEHOLDER = "@@WAN_PASSWORD@@"
+
+# Per-VLAN interface addresses of each node, read from the live boxes. VRRP
+# unicast (hello-source-address/peer-address) needs both ends explicitly, and
+# these are NOT derivable from the subnet -- VLAN 3 is .4/.5 while everything
+# else is .252/.253.
+#                vlan: (vyos001,          vyos002)
+NODE_ADDRS = {
+    1:   ("192.168.1.252", "192.168.1.253"),
+    2:   ("192.168.9.252", "192.168.9.253"),
+    3:   ("192.168.3.4",   "192.168.3.5"),
+    9:   ("10.8.0.252",    "10.8.0.253"),
+    10:  ("10.0.1.252",    "10.0.1.253"),
+    200: ("192.168.2.252", "192.168.2.253"),
+}
+
+# Dedicated point-to-point link for conntrack state sync (eth3 <-> eth3).
+CONNTRACK_ADDRS = ("10.255.255.1/30", "10.255.255.2/30")
+CONNTRACK_IF = "eth3"
+
+# kea HA talks over TCP 647. The LoT addresses are used because they are stable
+# and reachable today without the conntrack cable being plugged in.
+DHCP_HA_NAME = "vyos-dhcp-pair"     # must NOT equal either system host-name
+
+
+
+def vrrp_group(vlan: int) -> str:
+    """VRRP group names as configured on the boxes: 'native' for the untagged
+    VLAN, 'vlan<id>' otherwise."""
+    return "native" if vlan == 1 else f"vlan{vlan}"
+
+
+def build_delta(inv: dict, priority: int, wan_user: str, with_wan: bool,
+                conntrack_link: bool) -> list[str]:
+    out: list[str] = []
+    primary = priority >= 200          # vyos001 is the master/primary
+    self_i, peer_i = (0, 1) if primary else (1, 0)
+    nets = [n for n in inv["networks"] if n["dhcp_enabled"] and n["subnet"]]
+    nets.sort(key=unifi_to_vyos.vlan_of)
+
+    out += [
+        "# ==========================================================",
+        "# Delta: passive VyOS pair -> gateway. Applied on top of a",
+        "# freshly loaded unifi.boot, never on top of itself.",
+        "# ==========================================================",
+        "",
+        "# An unconfirmed commit must reload the previous config, NOT reboot.",
+        "# 'reboot' is the VyOS default and would turn a failed switch into a",
+        "# real outage on the box that is meant to be carrying the network.",
+        "set system config-management commit-confirm action reload",
+        "",
+        "# --- gateway addresses ------------------------------------",
+        "# The VIP takes over the address the USG holds today, so no client",
+        "# changes anything: no renewal needed, hardcoded gateways keep working.",
+    ]
+    for n in nets:
+        vlan = unifi_to_vyos.vlan_of(n)
+        grp = vrrp_group(vlan)
+        iface = ipaddress.ip_interface(n["subnet"])
+        out.append(f"# {n['name']} (VLAN {vlan}) -> {iface.with_prefixlen}")
+        # Delete the whole address node rather than a computed old value.
+        # `address` is multi-value, and the current VIPs are NOT at
+        # network+254 on the /23 networks -- they are 192.168.9.254,
+        # 10.0.9.254 and 10.0.1.254, in the upper half. A delete naming the
+        # wrong address fails quietly and leaves the group holding two VIPs.
+        out.append(f"delete high-availability vrrp group {grp} address")
+        out.append(f"set high-availability vrrp group {grp} address {iface.with_prefixlen}")
+        out.append(f"set high-availability vrrp group {grp} priority {priority}")
+        own, peer = NODE_ADDRS[vlan] if primary else NODE_ADDRS[vlan][::-1]
+        # Unicast VRRP: the walkthrough sets both ends explicitly rather than
+        # relying on multicast, which is more predictable across a switch fabric.
+        out.append(f"set high-availability vrrp group {grp} hello-source-address {own}")
+        out.append(f"set high-availability vrrp group {grp} peer-address {peer}")
+        # Without no-preempt a recovered box reclaims the VIP immediately --
+        # before conntrack state has synced -- and drops every established
+        # connection. If preemption is ever wanted, preempt-delay must be >=
+        # the conntrack-sync purge-timeout.
+        out.append(f"set high-availability vrrp group {grp} no-preempt")
+
+    out += [
+        "",
+    ]
+
+
+    out += [
+        "",
+        "# --- stateful tracking (BOTH boxes) ------------------------",
+        "# VyOS only engages conntrack when a firewall or NAT exists. The",
+        "# backup has no WAN and therefore no NAT, so without this rule it",
+        "# tracks nothing -- and conntrack-sync entries replicated to a box",
+        "# whose conntrack is not engaged cannot be used when it takes over.",
+        "# Verified in labsim: zero conntrack entries until a state-matching",
+        "# rule was present, then replication began immediately.",
+        "set firewall ipv4 forward filter default-action accept",
+        "set firewall ipv4 forward filter rule 10 action accept",
+        "set firewall ipv4 forward filter rule 10 state established",
+        "set firewall ipv4 forward filter rule 10 state related",
+        "set firewall ipv4 forward filter rule 10 description 'stateful tracking'",
+    ]
+
+    if True:  # WAN config on BOTH boxes; see the disable block below
+        out += [
+            "# --- WAN -----------------------------------------------",
+            "# Both vifs must be created before anything references them.",
+            "# Neither firewall has vif 51 or 53 today (only 2, 3, 9, 10, 200),",
+            "# and pppoe source-interface points at an interface that must",
+            "# already exist -- without this the commit fails and, since the",
+            "# delta commits as one unit, takes the whole switch with it.",
+            f"set interfaces bonding bond0 vif {WAN_PPPOE_VIF.split('.')[1]} description 'WAN1 Vodafone (PPPoE)'",
+            f"set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} description 'WAN2 10gig ISP (DHCP)'",
+            "",
+            "# WAN2, the 10 gig line -- primary. The cloned MAC is what keeps",
+            "# the existing public lease (87.192.101.48) instead of asking for",
+            "# a new one. Only the box carrying the WAN may set this.",
+            f"set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} mac '{WAN_DHCP_MAC}'",
+            f"set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} address dhcp",
+            # Demoted below Vodafone; `protocols failover` owns the live route.
+            # NOT no-default-route -- that blanks new_routers in the lease and
+            # leaves the failover daemon with no gateway to install.
+            f"set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} dhcp-options default-route-distance {DIST_DHCP_FALLBACK}",
+            "",
+            "# WAN1, Vodafone -- failover at a higher distance. Verified working",
+            "# on the USG: pppoe0 came up with a public address, MTU 1492.",
+            f"set interfaces pppoe {WAN_PPPOE_IF} source-interface {WAN_PPPOE_VIF}",
+            f"set interfaces pppoe {WAN_PPPOE_IF} authentication username '{wan_user}'",
+            f"set interfaces pppoe {WAN_PPPOE_IF} authentication password '{PLACEHOLDER}'",
+            f"set interfaces pppoe {WAN_PPPOE_IF} mtu 1492",
+            f"set interfaces pppoe {WAN_PPPOE_IF} default-route-distance {DIST_PPPOE}",
+            # The peer's resolvers would otherwise overwrite resolv.conf.
+            f"set interfaces pppoe {WAN_PPPOE_IF} no-peer-dns",
+            "",
+            "# The static default route exists only for unifi mode, where the",
+            "# USG is the next hop. Both WANs supply one here.",
+            "delete protocols static route 0.0.0.0/0",
+            "",
+            "# --- Health-checked primary ----------------------------",
+            "# Without this, failover only fires when bond0.53 loses carrier",
+            "# or its lease. An ISP that keeps the link up while dropping",
+            "# traffic -- the common failure -- would black-hole everything,",
+            "# because a DHCP-installed route has nothing to withdraw it.",
+            "#",
+            "# vyos-failover pings each target bound to the interface",
+            "# (`ping -I bond0.53`), so the backup can never be validated",
+            "# through the primary's path and vice versa. On withdrawal the",
+            "# kernel falls through to Vodafone's distance-10 route.",
+            f"set protocols failover route 0.0.0.0/0 dhcp-interface {WAN_DHCP_VIF} check type icmp",
+            f"set protocols failover route 0.0.0.0/0 dhcp-interface {WAN_DHCP_VIF} check policy any-available",
+            f"set protocols failover route 0.0.0.0/0 dhcp-interface {WAN_DHCP_VIF} check timeout {FAILOVER_TIMEOUT}",
+            f"set protocols failover route 0.0.0.0/0 dhcp-interface {WAN_DHCP_VIF} metric {FAILOVER_METRIC}",
+            *[
+                f"set protocols failover route 0.0.0.0/0 dhcp-interface {WAN_DHCP_VIF} check target {t}"
+                for t in FAILOVER_TARGETS
+            ],
+            "",
+            "# --- NAT -----------------------------------------------",
+            f"set nat source rule 100 outbound-interface name {WAN_DHCP_VIF}",
+            "set nat source rule 100 translation address masquerade",
+            "set nat source rule 100 description 'LAN out via the 10gig line'",
+            f"set nat source rule 110 outbound-interface name {WAN_PPPOE_IF}",
+            "set nat source rule 110 translation address masquerade",
+            "set nat source rule 110 description 'LAN out via Vodafone (failover)'",
+        ]
+
+    if not with_wan:
+        # The backup carries the identical WAN and NAT config but with the
+        # interfaces administratively DOWN. The cloned MAC is therefore never
+        # live on two boxes at once, while everything needed to route and
+        # masquerade is already present -- taking over is enabling two
+        # interfaces, not rebuilding a config under pressure.
+        #
+        # NAT rules naming a down interface are harmless: VyOS warns at commit
+        # ("Interface ... does not exist!") and commits anyway, verified.
+        out += [
+            "",
+            "# --- WAN held DOWN on this box -----------------------------",
+            "# Enable these two to take over the internet path:",
+            f"#   set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} disable  <- delete this",
+            f"#   set interfaces pppoe {WAN_PPPOE_IF} disable                <- and this",
+            f"set interfaces bonding bond0 vif {WAN_DHCP_VIF.split('.')[1]} disable",
+            f"set interfaces pppoe {WAN_PPPOE_IF} disable",
+        ]
+
+    if True:
+        # Port forwards and the WAN firewall go on BOTH boxes. They name
+        # interfaces that are present-but-disabled on the backup, which VyOS
+        # accepts (it warns and commits). Putting them here means a failover is
+        # enabling an interface, not reconstructing NAT under pressure.
+        # Port forwards, straight from UniFi.
+        for i, p in enumerate(inv["port_forwards"]):
+            if not p.get("enabled"):
+                continue
+            rule = 100 + i * 10
+            proto = p["proto"]  # tcp | udp | tcp_udp -- all valid VyOS values
+            out += [
+                "",
+                f"set nat destination rule {rule} description '{p['name']}'",
+                f"set nat destination rule {rule} inbound-interface name {WAN_DHCP_VIF}",
+                f"set nat destination rule {rule} protocol {proto}",
+                f"set nat destination rule {rule} destination port '{p['dst_port']}'",
+                f"set nat destination rule {rule} translation address {p['fwd']}",
+            ]
+            # `destination port` accepts a comma list but `translation port` does
+            # NOT -- "16881,6881 is not a valid service name" -- because mapping a
+            # list onto a list is ambiguous. Every forward here maps a port to
+            # itself, and omitting translation port makes VyOS preserve the
+            # original, which is exactly right. Only emit it when it genuinely
+            # differs, and refuse rather than guess when a differing list appears.
+            if p["fwd_port"] != p["dst_port"]:
+                if "," in str(p["fwd_port"]) or "," in str(p["dst_port"]):
+                    raise SystemExit(
+                        f"port forward '{p['name']}' remaps a LIST of ports "
+                        f"({p['dst_port']} -> {p['fwd_port']}). VyOS cannot express "
+                        f"that in one rule; split it into one rule per port by hand.")
+                out.append(f"set nat destination rule {rule} translation port '{p['fwd_port']}'")
+
+        out += [
+            "",
+            "# --- firewall ----------------------------------------------",
+            "# VyOS defaults to accepting everything. The USG has an implicit",
+            "# WAN drop, so migrating the port forwards alone would leave the",
+            "# router's own services and the whole LAN reachable from the WAN.",
+            "#",
+            "# Scoped to the WAN interface rather than a global default-action",
+            "# drop: that way a mistake here cannot lock anyone out over the LAN,",
+            "# which is the only path back in during a cutover.",
+            "",
+            "# Traffic TO the router.",
+            "set firewall ipv4 input filter default-action accept",
+            "set firewall ipv4 input filter rule 100 action accept",
+            "set firewall ipv4 input filter rule 100 state established",
+            "set firewall ipv4 input filter rule 100 state related",
+            "set firewall ipv4 input filter rule 100 description 'established/related'",
+        ]
+        # The two WAN_LOCAL accepts carried over from UniFi.
+        out += [
+            "",
+            "set firewall ipv4 input filter rule 110 action accept",
+            "set firewall ipv4 input filter rule 110 protocol esp",
+            f"set firewall ipv4 input filter rule 110 inbound-interface name {WAN_DHCP_VIF}",
+            "set firewall ipv4 input filter rule 110 description 'VPN accept ESP (from UniFi WAN_LOCAL)'",
+            "",
+            "set firewall ipv4 input filter rule 120 action accept",
+            "set firewall ipv4 input filter rule 120 protocol udp",
+            "set firewall ipv4 input filter rule 120 destination port '500,4500'",
+            f"set firewall ipv4 input filter rule 120 inbound-interface name {WAN_DHCP_VIF}",
+            "set firewall ipv4 input filter rule 120 description 'VPN accept UDP500/4500 (from UniFi WAN_LOCAL)'",
+            "",
+            "set firewall ipv4 input filter rule 130 action accept",
+            "set firewall ipv4 input filter rule 130 protocol icmp",
+            f"set firewall ipv4 input filter rule 130 inbound-interface name {WAN_DHCP_VIF}",
+            "set firewall ipv4 input filter rule 130 description 'ICMP to the router (path MTU discovery)'",
+            "",
+            "# Everything else arriving from the WAN is dropped. LAN is untouched.",
+            "set firewall ipv4 input filter rule 900 action drop",
+            f"set firewall ipv4 input filter rule 900 inbound-interface name {WAN_DHCP_VIF}",
+            f"set firewall ipv4 input filter rule 910 action drop",
+            f"set firewall ipv4 input filter rule 910 inbound-interface name {WAN_PPPOE_IF}",
+            "set firewall ipv4 input filter rule 910 description 'drop all other WAN-to-router (Vodafone)'",
+            "set firewall ipv4 input filter rule 900 description 'drop all other WAN-to-router'",
+            "",
+            "# Traffic THROUGH the router.",
+            "set firewall ipv4 forward filter default-action accept",
+            "set firewall ipv4 forward filter rule 100 action accept",
+            "set firewall ipv4 forward filter rule 100 state established",
+            "set firewall ipv4 forward filter rule 100 state related",
+            "set firewall ipv4 forward filter rule 100 description 'established/related'",
+        ]
+
+        # Destination NAT happens before the forward filter, so these rules must
+        # match the translated destination, not the WAN address.
+        for i, p in enumerate(inv["port_forwards"]):
+            if not p.get("enabled"):
+                continue
+            rule = 200 + i * 10
+            out += [
+                "",
+                f"set firewall ipv4 forward filter rule {rule} action accept",
+                f"set firewall ipv4 forward filter rule {rule} inbound-interface name {WAN_DHCP_VIF}",
+                f"set firewall ipv4 forward filter rule {rule} protocol {p['proto']}",
+                f"set firewall ipv4 forward filter rule {rule} destination address {p['fwd']}",
+                f"set firewall ipv4 forward filter rule {rule} destination port '{p['fwd_port']}'",
+                f"set firewall ipv4 forward filter rule {rule} description 'port forward: {p['name']}'",
+            ]
+
+        out += [
+            "",
+            "# New inbound connections from the WAN that are not a port forward.",
+            "set firewall ipv4 forward filter rule 900 action drop",
+            f"set firewall ipv4 forward filter rule 900 inbound-interface name {WAN_DHCP_VIF}",
+            f"set firewall ipv4 forward filter rule 910 action drop",
+            f"set firewall ipv4 forward filter rule 910 inbound-interface name {WAN_PPPOE_IF}",
+            "set firewall ipv4 forward filter rule 910 description 'drop unsolicited WAN-to-LAN (Vodafone)'",
+            "set firewall ipv4 forward filter rule 900 description 'drop unsolicited WAN-to-LAN'",
+            "",
+        ]
+
+
+    # --- DHCP high-availability -------------------------------------------
+    # Without this BOTH boxes run kea on the same VLANs and race to answer the
+    # same broadcasts, handing different pool addresses to the same client.
+    # active-passive so only the primary serves, matching the VRRP shape.
+    dhcp_self, dhcp_peer = NODE_ADDRS[10][self_i], NODE_ADDRS[10][peer_i]
+    out += [
+        "",
+        "# --- DHCP high-availability --------------------------------",
+        "# Peers sync leases over TCP 647. Each subnet already carries a",
+        "# unique subnet-id (keyed on VLAN id), which kea HA requires.",
+        "set service dhcp-server high-availability mode active-passive",
+        f"set service dhcp-server high-availability status {'primary' if primary else 'secondary'}",
+        # The peer name must not collide with either system host-name.
+        f"set service dhcp-server high-availability name {DHCP_HA_NAME}",
+        f"set service dhcp-server high-availability source-address {dhcp_self}",
+        f"set service dhcp-server high-availability remote {dhcp_peer}",
+    ]
+
+    if conntrack_link:
+        # Stateful failover. Without it VRRP moves the address but every
+        # established connection dies, because the backup has no conntrack
+        # table. Needs the eth3 <-> eth3 cable physically present.
+        out += [
+            "",
+            "# --- conntrack-sync ----------------------------------------",
+            "# Dedicated point-to-point link: sync traffic must not compete",
+            "# with production, and must not die when the LAN does.",
+            f"set interfaces ethernet {CONNTRACK_IF} address {CONNTRACK_ADDRS[self_i]}",
+            f"set interfaces ethernet {CONNTRACK_IF} description 'conntrack-sync peer link'",
+            f"set service conntrack-sync interface {CONNTRACK_IF}",
+            "set service conntrack-sync failover-mechanism vrrp sync-group MAIN",
+            "set service conntrack-sync accept-protocol tcp",
+            "set service conntrack-sync accept-protocol udp",
+            "set service conntrack-sync accept-protocol icmp",
+            "set service conntrack-sync mcast-group 225.0.0.50",
+        ]
+
+    # DHCP + DNS, from the same generator labsim proved.
+    dhcp_lines, stats = unifi_to_vyos.build(inv, "prod")
+    expected = len(inv["reservations"])
+    if stats["mappings"] != expected:
+        raise SystemExit(
+            f"refusing to generate: {expected - stats['mappings']} reservation(s) "
+            f"missing -- every one must survive the cutover")
+    out += dhcp_lines
+    return out
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--priority", type=int, required=True,
+                    help="VRRP priority: 200 for the master, 100 for the backup")
+    ap.add_argument("--inventory", default=os.path.join(HERE, "export", "inventory.json"))
+    ap.add_argument("--raw-networkconf", default=os.path.join(HERE, "export", "rest_networkconf.json"))
+    ap.add_argument("--with-wan", action="store_true",
+                help="configure the WAN on this box. Only ONE of the pair may have\n                      it, because the cloned WAN MAC must be unique.")
+    ap.add_argument("--conntrack-link", action="store_true",
+                    help="emit conntrack-sync over the eth3 peer link. Requires the\n                          cable to be physically present on both boxes.")
+    ap.add_argument("-o", "--out")
+    ap.add_argument("--emit-secrets", metavar="PATH",
+                    help="write the PPPoE credential to PATH with mode 0600 and exit")
+    args = ap.parse_args()
+
+    with open(args.inventory) as fh:
+        inv = json.load(fh)
+    with open(args.raw_networkconf) as fh:
+        raw_nets = json.load(fh)
+
+    wan = next((n for n in raw_nets
+                if n.get("purpose") == "wan" and n.get("wan_username")), None)
+    if wan is None:
+        print("no WAN network with credentials found in the export", file=sys.stderr)
+        return 1
+
+    if args.emit_secrets:
+        fd = os.open(args.emit_secrets, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
+        with os.fdopen(fd, "w") as fh:
+            fh.write(f"WAN_PASSWORD='{wan.get('x_wan_password', '')}'\n")
+        # Re-assert the mode in case the file already existed with a wider one.
+        os.chmod(args.emit_secrets, 0o600)
+        mode = oct(os.stat(args.emit_secrets).st_mode & 0o777)
+        print(f"wrote {args.emit_secrets} (mode {mode}) for user {wan['wan_username']}",
+              file=sys.stderr)
+        return 0
+
+    lines = build_delta(inv, args.priority, wan["wan_username"], args.with_wan,
+                        args.conntrack_link)
+    text = "\n".join(lines) + "\n"
+
+    # Only a WAN-carrying delta has a credential to placeholder-substitute.
+    if args.with_wan and PLACEHOLDER not in text:
+        print("BUG: password placeholder missing from a WAN delta", file=sys.stderr)
+        return 1
+    if wan.get("x_wan_password") and wan["x_wan_password"] in text:
+        print("BUG: the WAN password leaked into the delta", file=sys.stderr)
+        return 1
+
+    n_set = sum(1 for l in lines if l.startswith("set "))
+    n_del = sum(1 for l in lines if l.startswith("delete "))
+    print(f"delta: {n_set} set, {n_del} delete, priority {args.priority}, "
+          f"{len(inv['reservations'])} reservations", file=sys.stderr)
+
+    if args.out:
+        with open(args.out, "w") as fh:
+            fh.write(text)
+        print(f"wrote {args.out}", file=sys.stderr)
+    else:
+        sys.stdout.write(text)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

migration/vyos-unifi-switch

@@ -0,0 +1,304 @@
+#!/bin/bash
+# Switch this VyOS box between passive (USG is the gateway) and active
+# (VyOS is the gateway). Installed at /config/vyos-unifi-switch, which
+# survives image upgrades, so it can be run from a local terminal or the
+# JetKVM console with no workstation and no internet.
+#
+#   vyos-unifi-switch            report the current mode
+#   vyos-unifi-switch vyos       take over: VIPs to .1, DHCP, DNS, PPPoE, NAT
+#   vyos-unifi-switch unifi      revert; the USG can then be reconnected
+#
+# READ THIS BEFORE THE CUTOVER
+#
+# `unifi` is the escape hatch. It runs no health checks, asks no questions and
+# has nothing that can refuse. If anything at all looks wrong, run it, then
+# plug the USG back in.
+#
+# `vyos` commits with commit-confirm. If it is not confirmed -- because the
+# health checks failed, or because you lost access, or because you walked away
+# -- the box returns to the saved configuration on its own. That requires
+# `system config-management commit-confirm action reload`; without it VyOS
+# REBOOTS instead, which on a gateway is an outage rather than an undo. The
+# script refuses to run if that setting is missing.
+set -uo pipefail
+
+MODES=/config/modes
+UNIFI_BOOT="$MODES/unifi.boot"
+DELTA="$MODES/to-vyos.commands"
+SECRETS=/config/wan-secrets
+MARKER="$MODES/current-mode"
+CONFIRM_MINUTES="${CONFIRM_MINUTES:-10}"
+OPRUN=/opt/vyatta/bin/vyatta-op-cmd-wrapper
+
+say()  { printf '[switch] %s\n' "$*"; }
+warn() { printf '[switch] WARNING: %s\n' "$*" >&2; }
+die()  { printf '[switch] ERROR: %s\n' "$*" >&2; exit 1; }
+
+# Run configuration commands in a real config session. Everything the caller
+# feeds in runs between `configure` and `exit`.
+run_cfg() {
+  local script rc
+  script="$(mktemp)"
+  {
+    echo 'source /opt/vyatta/etc/functions/script-template'
+    echo 'configure'
+    cat
+    echo 'exit'
+  } > "$script"
+  vbash "$script"; rc=$?
+  rm -f "$script"
+  return $rc
+}
+
+# Two traps live in this one function, both of which produced wrong answers
+# rather than errors:
+#   1. `show configuration commands` quotes values ("action 'reload'"), so the
+#      quotes have to go before matching or every value-bearing check fails.
+#   2. `... | grep -q` under `set -o pipefail` reports FAILURE even on a match:
+#      grep exits at the first hit, the producer takes SIGPIPE, and pipefail
+#      surfaces that. Whether it triggers depends on output size, so it fails
+#      intermittently. Match against a captured string instead of a pipeline.
+cfg_has() {
+  local out
+  out="$($OPRUN show configuration commands 2>/dev/null | tr -d "'")"
+  case "$out" in *"$1"*) return 0 ;; *) return 1 ;; esac
+}
+
+# ---------------------------------------------------------------- status ----
+current_mode() {
+  # The marker records intent; the running config is the truth. Report the
+  # config, and complain if the two disagree.
+  local live="unknown"
+  if cfg_has "set service dhcp-server"; then live="vyos"; else live="unifi"; fi
+  echo "$live"
+}
+
+show_status() {
+  local live marked
+  live="$(current_mode)"
+  marked="$(cat "$MARKER" 2>/dev/null || echo "never set")"
+  echo "host:          $(hostname)"
+  echo "mode:          $live   (marker: $marked)"
+  [ "$live" != "$marked" ] && [ "$marked" != "never set" ] && \
+    warn "marker disagrees with the running config -- trust the config"
+  echo "VRRP:"
+  $OPRUN show vrrp 2>/dev/null | sed -n '3,$p' | awk '{printf "               %-9s %-12s %s\n", $1, $2, $4}'
+  echo "DHCP server:   $(systemctl is-active isc-kea-dhcp4-server 2>/dev/null)"
+  echo "DNS forwarder: $(systemctl is-active pdns-recursor 2>/dev/null)"
+  echo "WAN (pppoe0):  $(ip -4 -br addr show pppoe0 2>/dev/null | awk '{print $2, $3}' || echo 'not present')"
+  echo "default route: $(ip -4 route show default 2>/dev/null | head -1 || echo none)"
+  echo "unsaved changes: $(cfg_unsaved)"
+}
+
+cfg_unsaved() {
+  if /usr/bin/config-mgmt compare >/dev/null 2>&1; then echo "no"; else echo "possibly - check 'compare saved'"; fi
+}
+
+# ------------------------------------------------------------- preflight ----
+require_files() {
+  [ -r "$UNIFI_BOOT" ] || die "missing $UNIFI_BOOT -- capture it while the USG is still the gateway"
+  [ -s "$UNIFI_BOOT" ] || die "$UNIFI_BOOT is empty"
+}
+
+require_reload_action() {
+  cfg_has "set system config-management commit-confirm action reload" && return 0
+  die "commit-confirm action is not 'reload'. Without it an unconfirmed switch
+       REBOOTS this box instead of reverting. Fix first:
+         configure
+         set system config-management commit-confirm action reload
+         commit; save"
+}
+
+# The single worst outcome available is two devices answering on the gateway
+# address. It costs one ARP probe to make that impossible.
+# Returns 0 (success) when something IS answering on a gateway address we are
+# about to claim -- i.e. "yes, still alive, do not proceed".
+usg_still_alive() {
+  local found=0 ip dev targets
+  targets="$(grep -oE "vrrp group [a-z0-9]+ address [0-9.]+" "$DELTA" 2>/dev/null | awk '{print $NF}')"
+  if [ -z "$targets" ]; then
+    # A delta with no VIPs cannot be probed, which means the single guard
+    # against two devices sharing a gateway address is inert. Refuse by
+    # default: an unprobeable delta on the real boxes is a broken delta, and
+    # "warn and continue" would let the one failure this script exists to
+    # prevent through unnoticed. The override is for the lab only.
+    if [ "${ALLOW_NO_VIP_DELTA:-0}" = "1" ]; then
+      warn "delta claims no VIPs; proceeding because ALLOW_NO_VIP_DELTA=1 (lab only)"
+      return 1
+    fi
+    die "this delta claims no VIPs, so the gateway-address guard cannot run.
+       On the real boxes that means a broken delta. If this really is a lab
+       run, re-invoke with ALLOW_NO_VIP_DELTA=1."
+  fi
+  for ip in $targets; do
+    dev="$(ip -4 route get "$ip" 2>/dev/null | sed -n 's/.* dev \([^ ]*\).*/\1/p' | head -1)"
+    if [ -n "$dev" ] && command -v arping >/dev/null 2>&1; then
+      # ARP is the right probe: it answers even when the host filters ICMP.
+      if arping -c 2 -w 3 -f -I "$dev" "$ip" >/dev/null 2>&1; then
+        warn "something already answers ARP on $ip (via $dev)"; found=1
+      fi
+    elif ping -c 2 -W 2 "$ip" >/dev/null 2>&1; then
+      warn "something already answers ICMP on $ip"; found=1
+    fi
+  done
+  [ "$found" -eq 1 ]
+}
+
+# ------------------------------------------------------------- to unifi -----
+to_unifi() {
+  require_files
+  say "reverting to unifi mode (USG is the gateway)"
+  run_cfg <<EOF || die "load/commit failed -- the box is unchanged, use the console"
+load $UNIFI_BOOT
+commit
+save
+EOF
+  echo "unifi" > "$MARKER"
+  say "done. The USG can be reconnected."
+  say "If it was already connected during this, nothing was disturbed."
+}
+
+# -------------------------------------------------------------- to vyos -----
+health_checks() {
+  local fails=0
+  _chk() { # name, command
+    if eval "$2" >/dev/null 2>&1; then say "  ok    $1"; else say "  FAIL  $1"; fails=$((fails+1)); fi
+  }
+  _chk "kea (DHCP) is running"      "systemctl is-active --quiet isc-kea-dhcp4-server"
+  _chk "DNS forwarder is running"   "systemctl is-active --quiet pdns-recursor"
+
+  # Only assert on the WAN if this delta actually brings one up. A delta with
+  # no PPPoE stanza is a lab/partial delta, and failing it on a missing
+  # pppoe0 would make the script untestable anywhere but the live cutover.
+  # Announced loudly, because a quietly skipped check is worse than no check.
+  # A box whose delta holds its WAN interfaces DOWN is the backup: it has no
+  # route out by design, and demanding one reverts a perfectly correct config.
+  # This tore down vyos002 on the first successful cutover -- vyos001 went live
+  # and its backup was judged unhealthy for lacking the WAN it is deliberately
+  # not carrying. Same mistake as requiring the failover line: checks that do
+  # not apply to the box being checked.
+  if grep -qE "^set interfaces (pppoe pppoe0|bonding bond0 vif 53) disable$" "$DELTA"; then
+    say "  note  this box holds its WAN down (backup); skipping WAN checks"
+  elif grep -qE "^set interfaces (pppoe|bonding bond0 vif 5)" "$DELTA"; then
+    # What matters is that SOME WAN works, not that every WAN works.
+    #
+    # This reverted a cutover that had genuinely succeeded. The 10 gig line came
+    # up on bond0.53 and the cloned MAC was handed the same public address the
+    # USG had (87.192.101.48); kea was serving real LAN clients at the same
+    # moment. The only failure was pppoe0 -- the Vodafone FAILOVER line -- and
+    # requiring it undid a working gateway.
+    #
+    # Written as [ -n "$(...)" ] rather than `... | grep -q` for the pipefail
+    # reason above: a pipeline ending in grep -q cannot be trusted here.
+    _chk "a default route exists"   '[ -n "$(ip -4 route show default)" ]'
+    _chk "internet reachable"       "ping -c2 -W3 8.8.8.8"
+    _chk "DNS resolves through us"  "getent hosts vyos.net"
+
+    # Informational only: report each WAN, fail on neither. A failover line
+    # being down is worth seeing, not worth reverting for.
+    for _w in pppoe0 bond0.53; do
+      if [ -n "$(ip -4 -br addr show "$_w" 2>/dev/null | awk '{print $3}')" ]; then
+        say "  ok    WAN $_w has an address (informational)"
+      else
+        say "  note  WAN $_w has no address (informational, not fatal)"
+      fi
+    done
+  else
+    warn "this delta configures no WAN -- skipping all WAN health checks."
+    warn "That is expected in the lab and WRONG for the real cutover."
+  fi
+  return $fails
+}
+
+to_vyos() {
+  require_files
+  require_reload_action
+  [ -r "$DELTA" ] || die "missing $DELTA"
+
+  if usg_still_alive; then
+    die "refusing: something is still answering on a gateway address.
+       Disconnect the USG first. Two devices on the same gateway IP is the
+       one failure this script exists to prevent."
+  fi
+
+  local pw="" tmp
+  if [ -r "$SECRETS" ]; then
+    # shellcheck disable=SC1090
+    . "$SECRETS"; pw="${WAN_PASSWORD:-}"
+  fi
+  [ -n "$pw" ] || warn "no WAN_PASSWORD in $SECRETS -- PPPoE will not authenticate"
+
+  tmp="$(mktemp)"; chmod 600 "$tmp"
+  sed "s|@@WAN_PASSWORD@@|${pw}|g" "$DELTA" | grep -vE '^\s*(#|$)' > "$tmp"
+
+  say "switching to vyos mode (this box becomes the gateway)"
+  say "commit-confirm: ${CONFIRM_MINUTES} min to confirm, else it reverts itself"
+
+  # commit-confirm is TWO steps, and doing only the first commits nothing:
+  # `config-mgmt commit_confirm` arms the revert timer, then a normal `commit`
+  # applies the candidate config. The interactive prompt lives in the first
+  # step, which is why it is invoked directly with -y instead of via the
+  # `commit-confirm` alias. IN_COMMIT_CONFIRM is what the real CLI sets, and
+  # the commit hooks look at it.
+  if ! run_cfg < <(printf 'load %s\n' "$UNIFI_BOOT"; cat "$tmp";
+                   printf 'sudo sg vyattacfg "/usr/bin/config-mgmt commit_confirm -y -t=%s"\n' "$CONFIRM_MINUTES";
+                   printf 'export IN_COMMIT_CONFIRM=t\ncommit\nunset IN_COMMIT_CONFIRM\n'); then
+    rm -f "$tmp"
+    die "commit-confirm failed. Nothing was applied; the box is still in its
+       previous mode. Run '$0 unifi' if you are unsure."
+  fi
+  rm -f "$tmp"
+
+  # Poll, do not sample once.
+  #
+  # A cutover attempt failed here on a fixed 25s wait. That is far too short for
+  # a WAN: PPPoE is PADI/PADO/PADR/PADS then LCP, auth and IPCP, routinely 15-30s
+  # by itself, and both lines had just been released by the USG seconds earlier.
+  # ISPs commonly hold the previous session and MAC binding for minutes before
+  # leasing to the "same" CPE again -- which is precisely what a cloned MAC looks
+  # like to them. One sample at 25s reported a healthy setup as broken and
+  # reverted it.
+  #
+  # There is still a deadline, because commit-confirm is running: stop well
+  # before it so the decision is ours rather than the timer's.
+  local budget="${HEALTH_BUDGET:-180}" waited=0 step=15
+  say "committed. Polling health for up to ${budget}s (commit-confirm has ${CONFIRM_MINUTES} min)..."
+  while :; do
+    sleep "$step"; waited=$(( waited + step ))
+    if health_checks >/dev/null 2>&1; then
+      say "healthy after ${waited}s"
+      break
+    fi
+    if [ "$waited" -ge "$budget" ]; then
+      say "still unhealthy after ${waited}s -- final check:"
+      break
+    fi
+    say "  not healthy yet at ${waited}s, still waiting..."
+  done
+
+  say "health checks:"
+  if health_checks; then
+    say "all checks passed -- confirming"
+    /usr/bin/config-mgmt confirm >/dev/null 2>&1 || die "confirm failed; it will revert on its own shortly"
+    run_cfg <<'EOF' || warn "save failed -- config is live but will not survive a reboot"
+save
+EOF
+    echo "vyos" > "$MARKER"
+    say "vyos mode is live and saved."
+  else
+    warn "health checks FAILED -- reverting now rather than waiting out the timer"
+    /usr/bin/config-mgmt revert_soft >/dev/null 2>&1 \
+      || warn "revert_soft failed; the commit-confirm timer will still fire within ${CONFIRM_MINUTES} min"
+    echo "unifi" > "$MARKER"
+    die "reverted to the previous configuration. Reconnect the USG.
+       Check: ip addr show pppoe0; journalctl -u pppd; $0 status"
+  fi
+}
+
+# ----------------------------------------------------------------- main -----
+case "${1:-status}" in
+  vyos)   to_vyos ;;
+  unifi)  to_unifi ;;
+  status) show_status ;;
+  *)      echo "usage: $(basename "$0") [vyos|unifi|status]" >&2; exit 2 ;;
+esac

pulumi-vyos/Pulumi.labsim.yaml

@@ -0,0 +1 @@
+encryptionsalt: v1:tMNG4q79HiI=:v1:K35iEOw3pgyukCr6:LmKO37/jghjyT2sLuoLmCQIDPOIsgA==

pulumi-vyos/Pulumi.yaml

@@ -0,0 +1,3 @@
+name: vyos-proto
+runtime: nodejs
+description: Prototype — VyOS config subtrees as Pulumi resources, with commit-confirm

pulumi-vyos/README.md

@@ -0,0 +1,72 @@
+# VyOS as Pulumi resources — prototype
+
+Proves that VyOS config can be managed from the same Pulumi plan as the
+Kubernetes side, **without** giving up the safety property that matters on a
+gateway: a config push that breaks your access undoes itself.
+
+## Why not the community Terraform providers
+
+They are better than expected. `foltik/vyos`'s `vyos_config_block_tree` flattens
+an entire subtree into one payload and sends **one POST to `/configure`** —
+so one resource is one commit, not one commit per config line. That worry was
+unfounded.
+
+What they do *not* do is send `confirm_time`. The payload is only
+`op`/`path`/`value`, so every change is an unprotected commit. On a router you
+reach *through* the router, that is the difference between a mistake and an
+outage.
+
+## What the VyOS API actually supports
+
+Read from `rest/models.py` and `rest/routers.py` on the box, then verified by
+hand against a live router:
+
+- **Batching**: a list of operations in one request, applied as one commit.
+- **commit-confirm**: `confirm_time` on the request starts the revert timer.
+  Response says `Initialized commit-confirm; N minutes to confirm before reload`.
+
+Three details that cost time and are easy to get wrong:
+
+1. **`confirm_time` is only read when the body parses as `ConfigureListModel`** —
+   i.e. `{"commands": [...], "confirm_time": N}`. A **bare array** is accepted
+   and committed happily with **no timer armed**. It looks identical to success.
+   The resource therefore checks the response actually mentions commit-confirm
+   and refuses to continue if it does not.
+2. **There is no `/confirm` endpoint.** Confirming is an op on `/configure`.
+3. **Confirm still requires a `path` field**, even though it ignores it — the
+   Union resolves to `ConfigureModel`, which mandates `path`. Without it you get
+   `missing 'path' field` and the timer keeps running.
+
+## Shape
+
+One resource per **subtree**, not per line:
+
+```ts
+new VyosConfigTree("dns-forwarding", {
+    host, apiKey,
+    path: ["service", "dns", "forwarding"],
+    commands: [["cache-size", "20000"], ["name-server", "8.8.8.8"]],
+    confirmMinutes: 2,
+});
+```
+
+Apply is `delete <path>` + all the `set`s in one request, so the result is the
+declared state rather than a merge with whatever was there — which is what makes
+`pulumi up` converge instead of accumulate.
+
+## Verified on labsim
+
+- `pulumi up` create and update both land in ~6s, each a single
+  commit-confirmed transaction; update shows `[diff: ~commands]`.
+- Auto-revert observed: an unconfirmed commit returned the router to its saved
+  config on its own.
+- `pulumi destroy` removes the subtree.
+
+## Not done
+
+- The API is HTTP with a self-signed certificate and `rejectUnauthorized: false`.
+  Bind it to the management VLAN or the peer link and install a real
+  certificate before this goes near production.
+- No `refresh`/drift detection yet: `read` is not implemented, so out-of-band
+  changes are not noticed until the next `up` overwrites them.
+- The cutover itself should still use `vyos-unifi-switch`. This is for day-2.

pulumi-vyos/index.ts

@@ -0,0 +1,27 @@
+import * as pulumi from "@pulumi/pulumi";
+import { VyosConfigTree } from "./vyosConfigTree";
+
+const cfg = new pulumi.Config();
+const host = cfg.get("host") ?? "172.31.1.252";
+const apiKey = cfg.get("apiKey") ?? "labsim-proto-key";
+
+// One subtree, one resource, one commit. This is the shape a BGP change would
+// take: edit the commands array, `pulumi up`, and it lands as a single
+// commit-confirmed transaction alongside whatever Kubernetes resources changed
+// in the same plan.
+const dnsForwarding = new VyosConfigTree("dns-forwarding", {
+    host, apiKey,
+    path: ["service", "dns", "forwarding"],
+    commands: [
+        ["cache-size", "20000"],
+        ["listen-address", "172.31.10.1"],
+        ["allow-from", "172.31.10.0/23"],
+        ["name-server", "8.8.8.8"],
+        ["name-server", "8.8.4.4"],
+        ["name-server", "1.1.1.1"],
+    ],
+    confirmMinutes: 2,
+    save: true,
+});
+
+export const managed = dnsForwarding.id;

pulumi-vyos/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "vyos-proto",
+  "main": "index.ts",
+  "devDependencies": {
+    "@types/node": "^22",
+    "typescript": "^5.9.3"
+  },
+  "dependencies": {
+    "@pulumi/pulumi": "^3.140.0"
+  }
+}

pulumi-vyos/tsconfig.json

@@ -0,0 +1,2 @@
+{ "compilerOptions": { "strict": true, "target": "es2020", "module": "commonjs",
+  "moduleResolution": "node", "skipLibCheck": true, "esModuleInterop": true } }

pulumi-vyos/vyosConfigTree.ts

@@ -0,0 +1,205 @@
+import * as pulumi from "@pulumi/pulumi";
+import * as https from "https";
+
+/**
+ * A VyOS config subtree, managed as ONE Pulumi resource.
+ *
+ * Why a dynamic provider rather than the community Terraform providers: they
+ * batch correctly (one `vyos_config_block_tree` becomes a single POST to
+ * /configure, so one commit) but they never send `confirm_time`. VyOS's own API
+ * supports it -- `ConfigureListModel.confirm_time`, and "A non-zero confirm_time
+ * will start commit-confirm timer on commit" in rest/routers.py -- so a config
+ * push that breaks your access to the router can undo itself. On a gateway that
+ * is the difference between a mistake and an outage, and it is worth ~150 lines
+ * to keep.
+ *
+ * The unit of change is a SUBTREE, not a line. `protocols bgp` is one resource;
+ * so is `service dhcp-server`. That keeps one Pulumi resource == one commit,
+ * rather than turning 300 config lines into 300 commits with no ordering
+ * guarantee and no way to revert them as a unit.
+ */
+
+export interface VyosConfigTreeArgs {
+    /** Router address, e.g. "10.0.1.252". */
+    host: pulumi.Input<string>;
+    /** API key from `set service https api keys id <n> key <k>`. */
+    apiKey: pulumi.Input<string>;
+    /** Subtree root as a path array, e.g. ["protocols", "bgp"]. */
+    path: pulumi.Input<string[]>;
+    /**
+     * Desired state of the subtree: `set` command suffixes relative to `path`,
+     * each already split into path components with the value last.
+     */
+    commands: pulumi.Input<string[][]>;
+    /**
+     * Minutes before an unconfirmed commit reverts itself. 0 disables it.
+     * Non-zero is strongly preferred for anything reachable only through the
+     * router being changed.
+     */
+    confirmMinutes?: pulumi.Input<number>;
+    /** Persist to config.boot after a successful confirm. */
+    save?: pulumi.Input<boolean>;
+}
+
+interface Inputs {
+    host: string;
+    apiKey: string;
+    path: string[];
+    commands: string[][];
+    confirmMinutes: number;
+    save: boolean;
+}
+
+// Kept inside the module so the dynamic provider can serialise it.
+function apiCall(
+    host: string, apiKey: string, endpoint: string,
+    form: Record<string, string>,
+): Promise<any> {
+    const body = Object.entries(form)
+        .map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(v)}`)
+        .join("&");
+    return new Promise((resolve, reject) => {
+        const req = https.request({
+            host, port: 443, path: `/${endpoint}`, method: "POST",
+            // VyOS ships a self-signed certificate by default. Verification is
+            // disabled deliberately; if this ever leaves a trusted segment,
+            // install a real certificate and turn it back on.
+            rejectUnauthorized: false,
+            headers: {
+                "Content-Type": "application/x-www-form-urlencoded",
+                "Content-Length": Buffer.byteLength(body),
+            },
+            timeout: 120_000,
+        }, (res) => {
+            let data = "";
+            res.on("data", (c) => (data += c));
+            res.on("end", () => {
+                try {
+                    const parsed = JSON.parse(data);
+                    if (parsed.success === false) {
+                        reject(new Error(`VyOS API: ${parsed.error ?? data}`));
+                    } else {
+                        resolve(parsed);
+                    }
+                } catch {
+                    reject(new Error(`VyOS API returned non-JSON: ${data.slice(0, 300)}`));
+                }
+            });
+        });
+        req.on("error", reject);
+        req.on("timeout", () => { req.destroy(); reject(new Error("VyOS API timed out")); });
+        req.write(body);
+        req.end();
+    });
+}
+
+/**
+ * Replace a subtree: delete it, then set the desired state, in ONE request so
+ * it is a single commit. Deleting first makes the result the declared state
+ * rather than a merge with whatever was there -- which is what makes `pulumi
+ * up` converge instead of accumulating.
+ */
+async function applyTree(i: Inputs, desired: string[][]): Promise<void> {
+    const commands: any[] = [{ op: "delete", path: i.path }];
+    for (const c of desired) {
+        commands.push({ op: "set", path: [...i.path, ...c] });
+    }
+
+    // The payload MUST be {commands: [...], confirm_time: N}, not a bare array.
+    // VyOS only reads confirm_time when the body parses as ConfigureListModel
+    // (`if isinstance(data, (ConfigureModel, ConfigureListModel, ...))` in
+    // rest/routers.py). A bare array is accepted and committed happily -- with
+    // NO timer armed, silently discarding the safety net. Verified both ways:
+    // bare array gives no "Initialized commit-confirm" in the response, the
+    // object form returns "Initialized commit-confirm; N minutes to confirm".
+    const payload: any = { commands };
+    if (i.confirmMinutes > 0) payload.confirm_time = i.confirmMinutes;
+
+    const res = await apiCall(i.host, i.apiKey, "configure",
+                              { key: i.apiKey, data: JSON.stringify(payload) });
+
+    if (i.confirmMinutes > 0) {
+        // Refuse to continue if the timer did not actually arm -- otherwise a
+        // silent fallback to an unprotected commit is exactly the failure this
+        // resource exists to prevent.
+        const said = String((res && res.data) || "");
+        if (!said.includes("commit-confirm")) {
+            throw new Error(
+                "commit-confirm was requested but VyOS did not arm a timer " +
+                `(response: ${said.trim() || "<empty>"}). Refusing to proceed.`);
+        }
+    }
+
+    if (i.confirmMinutes > 0) {
+        // The commit landed but is on a timer. Reaching the API again proves
+        // the box is still answering *after* the change -- the only evidence
+        // worth confirming on. If this throws we deliberately do NOT confirm,
+        // and the router reverts itself.
+        await apiCall(i.host, i.apiKey, "retrieve", {
+            key: i.apiKey,
+            data: JSON.stringify({ op: "showConfig", path: [] }),
+        });
+        // There is no /confirm endpoint -- confirm is an op on /configure, and
+        // it requires a `path` field even though it ignores it (the Union
+        // resolves to ConfigureModel, which mandates path). Without it the API
+        // answers "missing 'path' field" and the timer keeps running.
+        await apiCall(i.host, i.apiKey, "configure", {
+            key: i.apiKey,
+            data: JSON.stringify({ op: "confirm", path: [] }),
+        });
+    }
+
+    if (i.save) {
+        await apiCall(i.host, i.apiKey, "config-file", {
+            key: i.apiKey, data: JSON.stringify({ op: "save" }),
+        });
+    }
+}
+
+const provider: pulumi.dynamic.ResourceProvider = {
+    async create(inputs: Inputs) {
+        await applyTree(inputs, inputs.commands);
+        return { id: `${inputs.host}:${inputs.path.join("/")}`, outs: inputs };
+    },
+
+    async update(_id, _old: Inputs, news: Inputs) {
+        await applyTree(news, news.commands);
+        return { outs: news };
+    },
+
+    async delete(_id, props: Inputs) {
+        const form: Record<string, string> = {
+            key: props.apiKey,
+            data: JSON.stringify([{ op: "delete", path: props.path }]),
+        };
+        if (props.confirmMinutes > 0) form.confirm_time = String(props.confirmMinutes);
+        await apiCall(props.host, props.apiKey, "configure", form);
+        if (props.confirmMinutes > 0) {
+            await apiCall(props.host, props.apiKey, "configure",
+                { key: props.apiKey, data: JSON.stringify({ op: "confirm", path: [] }) });
+        }
+    },
+
+    async diff(_id, olds: Inputs, news: Inputs) {
+        const changed =
+            JSON.stringify(olds.commands) !== JSON.stringify(news.commands) ||
+            JSON.stringify(olds.path) !== JSON.stringify(news.path) ||
+            olds.host !== news.host;
+        return {
+            changes: changed,
+            // Changing which subtree or which router is a different resource.
+            replaces: olds.host !== news.host ||
+                      JSON.stringify(olds.path) !== JSON.stringify(news.path) ? ["path"] : [],
+        };
+    },
+};
+
+export class VyosConfigTree extends pulumi.dynamic.Resource {
+    constructor(name: string, args: VyosConfigTreeArgs, opts?: pulumi.CustomResourceOptions) {
+        super(provider, name, {
+            confirmMinutes: 5,
+            save: true,
+            ...args,
+        }, opts);
+    }
+}