Home-Network/home-network-k3s-impl

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jakman85andClaude Opus 5 c8c1d2935d

gate / gate (push) Has been cancelled

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gate / conformance (push) Has been cancelled

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feat(dns): per-environment BASE_DOMAIN — prod moves to its own subdomain

INCIDENT FIX. Prod's external-dns DELETED EVERY ONE OF DEV'S PUBLIC DNS RECORDS. Both
clusters ran policy: sync against the SAME Cloudflare zone with the SAME implicit
txtOwnerId (`default`), so prod believed it owned dev's records, found no matching sources,
and removed them plus their TXT registry entries. Dev recovered ~30s after prod was scaled
to 0; verified restored against Cloudflare directly (my first check went through a pfSense
override and falsely showed healthy — local resolvers are not evidence about public DNS).

THE MISS WAS MINE, and it was a failure of imagination in how I briefed every agent. I put
"never touch dev" in brief after brief and enforced it — separate kubeconfigs, verified
--limit, sha-checked dev's kubeconfig before and after. Every one of those guards held. NONE
of them covered SHARED EXTERNAL RESOURCES. Prod reconciling its OWN correctly-authored
manifests reached across a third party and destroyed dev's state. Cluster-to-cluster
isolation was verified; the dependency that mattered was cluster-to-Cloudflare.

Operator's architecture: dev -> *.dev.home.keithjackson.dev, prod ->
*.prod.home.keithjackson.dev, apex CNAME <svc>.home -> <svc>.prod.home.

PHASE 1 ONLY (this commit): prod moves to its own subdomain. DEV IS NOT MIGRATED and its
effective hostname stays home.keithjackson.dev, so dev renders byte-identically and nothing
live moves. That alone ends the collision and unblocks prod. Phase 2 (dev -> dev.home. +
apex CNAMEs) is deferred to when the operator is present: it relocates Keycloak's issuer and
12 clients' redirect URIs, forces a rolling k3s restart and kubectl SSO re-issue for every
user, and moves gitea.home. — which is BOTH the GitOps source and the current push target.

BASE_DOMAIN WAS A DEAD KNOB — it existed in cluster-vars but the status report flagged it as
referenced by nothing, because hostnames were hardcoded throughout. Now real: 141 refs.
Searched the AUTHORITATIVE reconciled set by resolving each Flux spec.path transitively via
conformance/lib/status.py — the same resolver the L0 gate uses, so "what Flux reconciles"
has one definition. 185 occurrences across 47 files in 154 reconciled files. Tokenized:
Gateway listeners, the wildcard Certificate, coredns-custom, external-dns, Keycloak
instance/realm (26 redirect URIs), oauth2-proxy, Grafana OIDC, all HTTPRoutes, Homepage's 15
links, 30 runbook_urls, unifi cloud-init, render.py's ZONE constant (which drove
--oidc-issuer-url/--cookie-domain/--whitelist-domain on every forward-auth sidecar) and 11
catalog/ ServiceDefinitions re-rendered canonically. Left alone: 43 comment/prose
occurrences and non-reconciled paths.

TWO THAT CANNOT BE TOKENIZED, flagged not forced:
  - headlamp's OIDC URLs live inside a SOPS-encrypted Secret; re-encrypting rewrites the MAC
    over every value and the OFFLINE harness cannot verify it (kustomize does not decrypt),
    so an error would break live-dev SSO with no pre-flight proof. Prod needs its own copy
    anyway — client secrets are realm-scoped.
  - kube-apiserver --oidc-issuer-url is a k3s SERVER FLAG, not a manifest, so Flux can never
    reach it. Done on the inventory seam instead (k3s_base_domain -> k3s_oidc_issuer_url,
    overridden in group_vars/k3s_prod). Verified per host: dev keeps the default, prod gets
    prod.home.

EXTERNAL-DNS OWNER, the actual incident cause: txtOwnerId is now explicit per environment —
dev renders exactly `default` (the chart default it was already using, so its existing
records stay recognised) and prod gets `prod`. The BASE default is a NON-COLLIDING SENTINEL,
deliberately not `default`, so a future environment that forgets the knob owns nothing and
can delete nothing rather than silently inheriting dev's identity.

I OVERRODE ONE AGENT DECISION against our own prior finding: it narrowed prod's
domainFilters to prod.home.keithjackson.dev as defence in depth. FINDING F-DNS1
(DECISIONS-LOG 2026-08-17) already proved a subdomain filter DROPS THE PARENT ZONE —
ExternalDNS generates the record then skips it with "no hosted zone matching record DNS
Name". Prod would have published NOTHING. Set to the ZONE (keithjackson.dev) like dev.
Isolation comes from the subdomain split plus txtOwnerId, which is what the incident
actually needed and what a domain filter cannot provide.

DEV PROVEN UNCHANGED: 11 of 12 substituting paths byte-identical; the 12th differs by
exactly one line, `+ txtOwnerId: default` — the value dev was already using implicitly.
POSITIVE CONTROLS confirm the harness is not blind: perturbing BASE_DOMAIN moves 10 of 12
hashes (the 2 that don't provably contain no hostname), perturbing the owner id moves
exactly 1. Prod's rendered output has ZERO home.keithjackson.dev references outside prod.,
and its cert renders *.prod.home.keithjackson.dev — no overlap with dev's.

L0 substitution assertions 106 -> 254; BASE_DOMAIN is no longer flagged dead. Gate PASS.

PROD REMAINS SUSPENDED (platform + 10 downstream tiers) pending review; nothing applied.

Serves: R-ENV-02, R-DNS-01, R-DNS-02, R-DNS-03, R-TLS-01.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

2026-09-04 22:43:54 -05:00

headlamp-oidc-credentials.sops.yaml

fix(headlamp): rename OIDC secret keys to OIDC_* so chart args expand

2026-08-29 15:09:15 -05:00

headlamp-oidc-credentials.sops.yaml.example

fix(headlamp): rename OIDC secret keys to OIDC_* so chart args expand

2026-08-29 15:09:15 -05:00

helmrelease.yaml

fix(headlamp): rename OIDC secret keys to OIDC_* so chart args expand

2026-08-29 15:09:15 -05:00

helmrepository.yaml

platform: deploy Headlamp dashboard with Keycloak OIDC + per-user RBAC

2026-08-28 11:44:33 -05:00

httproute.yaml

feat(dns): per-environment BASE_DOMAIN — prod moves to its own subdomain

2026-09-04 22:43:54 -05:00

kustomization.yaml

platform: move Headlamp out of the gating platform tier + fix -session-ttl crashloop

2026-08-28 12:01:01 -05:00

namespace.yaml

platform: deploy Headlamp dashboard with Keycloak OIDC + per-user RBAC

2026-08-28 11:44:33 -05:00

networkpolicy.yaml

fix(net): allow SSO apps egress to keycloak backend (Cilium 1.20 CVE-2025-30162)

2026-08-30 23:34:03 -05:00

README.md

fix(headlamp): rename OIDC secret keys to OIDC_* so chart args expand

2026-08-29 15:09:15 -05:00

README.md

Headlamp — Kubernetes dashboard (Keycloak OIDC + per-user RBAC)

Headlamp is served at https://headlamp.home.keithjackson.dev behind the shared Gateway (wildcard TLS), with native Keycloak OIDC login and per-user RBAC (ADR-0014, docs/15).

How per-user RBAC works (end to end)

A user logs in at Keycloak (homelab realm, headlamp confidential client, auth-code flow).
Headlamp's backend keeps the user's id_token and forwards it as the bearer on every request it proxies to the k3s API server (this is Headlamp's default OIDC behaviour).
The apiserver validates that token — it is configured (infra/ansible roles/k3s_server) with oidc-issuer-url = this realm, oidc-client-id=kubernetes, oidc-username-claim=email, oidc-groups-claim=groups, prefixes oidc:.
RBAC is applied per user via the existing group bindings in ../keycloak/k8s-oidc-rbac.yaml: oidc:platform-admins → cluster-admin, oidc:viewers → view.

So each user gets exactly their own rights — not a shared Headlamp identity. That is why the Headlamp ServiceAccount is not bound to cluster-admin: the chart default clusterRoleBinding.create: true (→ cluster-admin) is overridden to false in helmrelease.yaml. User requests ride the forwarded user token; the SA needs no cluster rights.

The audience nuance (why the client has an audience mapper)

The apiserver only accepts ID tokens whose aud contains kubernetes (oidc-client-id= kubernetes). A plain headlamp client issues aud=[headlamp], which the apiserver would reject. The headlamp client therefore carries an oidc-audience-mapper (see ../keycloak/keycloak-realm-import.yaml) with included.client.audience: kubernetes, so tokens carry aud=[headlamp, kubernetes]:

Headlamp's own verifier accepts it (aud contains headlamp), and
the apiserver accepts it (aud contains kubernetes).

This keeps the apiserver OIDC config untouched (preferred over widening --api-audiences).

Secrets

The confidential client secret lives SOPS-encrypted in ../keycloak/keycloak-realm-clients.sops.yaml (headlamp-client-secret, injected into the realm import via the HEADLAMP_CLIENT_SECRET placeholder) and mirrored in this namespace's headlamp-oidc-credentials.sops.yaml (OIDC_CLIENT_SECRET), which the chart config.oidc.externalSecret envFrom's. Same cross-namespace mirror pattern as grafana/gitea.
Key names are load-bearing. The chart envFroms this Secret verbatim, so its keys become the container env vars referenced by the chart's OIDC args (-oidc-idp-issuer-url=$(OIDC_ISSUER_URL), etc.). They must be exactly OIDC_CLIENT_ID, OIDC_CLIENT_SECRET, OIDC_ISSUER_URL, OIDC_SCOPES (and OIDC_CALLBACK_URL) — not camelCase. A misnamed key leaves $(OIDC_ISSUER_URL) unexpanded and OIDC login fails with unsupported protocol scheme "".

Break-glass

The cert-based admin in the bootstrap kubeconfig is unaffected by any of this and retains full access if Keycloak/OIDC is down — the standard break-glass path.

Files

File	Tier	Purpose
`namespace.yaml`	platform	`headlamp` namespace (`gateway-access=shared`; platform, not app-namespace)
`helmrepository.yaml` / `helmrelease.yaml`	platform	Official `kubernetes-sigs/headlamp` chart + OIDC/RBAC values
`headlamp-oidc-credentials.sops.yaml`	platform	SOPS OIDC config the chart envFrom's (decrypted by the `platform` Flux Kustomization)
`networkpolicy.yaml`	platform	default-deny baseline + Cilium ingress(gateway)/egress(apiserver+Keycloak) allows
`httproute.yaml`	platform-config	Gateway API HTTPRoute for `headlamp.home.keithjackson.dev` (needs Gateway CRDs)