home-network-k3s-impl/platform/keycloak/README.md

# platform/keycloak

**Keycloak** — the platform Identity Provider (SSO via OIDC + SAML), onboarded early (Phase 6 IdP).

- **Governing ADR:** [ADR-0014 — IdP: Keycloak](../../../home-network-k3s/decisions/adr-0014-idp-keycloak.md)
- **Spec:** [docs/15 — Identity & Access](../../../home-network-k3s/docs/15-identity-and-access.md)
- **Serves:** R-IDP-01..06
- **Owner:** WS-SEC

## Image / tooling strategy (F-KY1 landmine avoided)

The original stub used the **Bitnami Keycloak chart + bundled Bitnami PostgreSQL**. Bitnami's free
Docker Hub images were purged (DECISIONS-LOG **F-KY1**) → that path ImagePullBackOffs. Replaced with:

- **Keycloak: the official Keycloak Operator** (`quay.io/keycloak/keycloak-operator` +
  `quay.io/keycloak/keycloak`, v26.0.6) driving a **`Keycloak` CR** + a **`KeycloakRealmImport` CR** for
  config-as-code (ADR-0014 permits Operator OR Helm; Operator gives clean CR-driven realm reconcile).
- **Database: CloudNativePG** (`ghcr.io/cloudnative-pg`, see [`../cnpg`](../cnpg)) — a `Cluster` on the
  3-replica **`longhorn`** StorageClass (DR-critical, R-IDP-05), with declarative backup hooks.

quay.io + ghcr.io are unaffected by the Bitnami purge. Operator manifests are pinned upstream release
files pulled as remote kustomize bases (the kubevirt-stub pattern); Renovate maintains the version.

## Layout (controllers / configs split — F-MON1)

| File | Applied by | What |
|---|---|---|
| `kustomization.yaml` (namespace, operator CRDs+Deployment, admin secret, dashboard) | **platform** | controllers |
| `keycloak-instance.yaml` (`Keycloak` CR, `${KEYCLOAK_REPLICAS}`) | **platform-config** | config |
| `postgres-cluster.yaml` (CNPG `Cluster` on longhorn) | **platform-config** | config |
| `keycloak-realm-import.yaml` (`KeycloakRealmImport`: realm/groups/clients/MFA) | **platform-config** | config |
| `client-secret-reconciler.yaml` (CronJob: client secrets **and** client URLs ← git, every 15m) | **platform-config** | config |
| `client-urls.yaml` (**GENERATED** ConfigMap: the client-URL desired state) | **platform-config** | config |
| `httproute.yaml` (keycloak.home.keithjackson.dev) | **platform-config** | config |
| `servicemonitor.yaml` (Prometheus scrape) | **platform-config** | config |

Realm config (groups `platform-admins`/`media-users`/`viewers`, OIDC clients `grafana`+`oauth2-proxy`,
brute-force ON, and a **conditional MFA browser flow that REQUIRES OTP for platform-admins**, R-IDP-04)
reconciles purely from git — no console clicking (R-IDP-03).

## Admin credential + break-glass (R-IDP-04 / R-IDP-05)

The provisioned `keycloak-admin-credentials.sops.yaml` (keys `admin-user`/`admin-password`) is injected
as the temporary **bootstrap/break-glass admin** via `KC_BOOTSTRAP_ADMIN_*` env (podTemplate escape
hatch) — this consumes the secret **as provisioned, without re-keying it** (the operator's native
`bootstrapAdmin` wants `username`/`password` keys, which would require editing the encrypted file).
The Keycloak bootstrap admin is the documented break-glass path so an IdP/SSO outage does not lock the
operator out (ADR-0014); Grafana likewise keeps its local admin login until SSO is proven.

## Operator hand-offs (fill before / during deploy)

1. **`keycloak-realm-clients.sops.yaml`** (keycloak ns) — from `.sops.yaml.example`. One
   `<clientId>-client-secret` key per confidential client, `openssl rand -hex 32` each. The realm
   import injects them into the Keycloak clients via `spec.placeholders`. Add to
   `kustomization.yaml` once filled.
   **The key name MUST be `<clientId>-client-secret`** — the reconciler below derives the clientId
   from it, and CI rejects any other name.
   *(This step used to read "the realm import stays PENDING until this exists". It does not — see
   the next section. That false belief is what allowed the 2026-09-06 outage.)*
2. **`../oauth2-proxy/oauth2-proxy-credentials.sops.yaml`** (oauth2-proxy ns) — `client-id: oauth2-proxy`,
   `client-secret` = the SAME `oauth2-proxy-client-secret` above, `cookie-secret` = `openssl rand -base64 32`.
3. **`../monitoring/grafana-oidc-credentials.sops.yaml`** (monitoring ns) — `client-secret` = the SAME
   `grafana-client-secret` above.

(Cross-namespace Secrets can't be shared, so each client secret is stored twice — once for the realm
import in `keycloak`, once for the consuming app.) See the two `.sops.yaml.example` templates for the
exact keys + steps. No plaintext secret is ever committed.

## Client secrets: the realm import fails OPEN, so a reconciler owns them (2026-09-06)

**The realm import is a one-shot that fails open.** Measured on both clusters:

* When the operator **cannot resolve** a `$(env:...)` placeholder it stores **the literal placeholder
  text** as the client secret — and the import Job still exits 0. There is no PENDING state, no
  error condition, and `HasErrors` stays `False`.
* Once complete the CR rests at **`Done=True` / `Started=False` and never re-runs**, so a Secret key
  added later is never picked up.

Together those produced a total SSO outage on prod (all 12 clients holding the literal placeholder;
every login rejected with *"Invalid client or Invalid client credentials"*) and a single broken client
on dev (`oauth2-proxy`, whose key was added after dev's import had already completed). Every cluster
signal was green throughout, including the conformance test that asserts `Done=True`.

Three layers now cover it:

| Layer | Where | What it does |
|---|---|---|
| **Prevent** | `conformance/tests/l0-static/keycloak-client-secret-reconciler` (runs on every merge, unconditionally, from `ci/l0.sh`) | Every placeholder is defined, reads `keycloak-realm-clients`, and names an **existing** key called `<clientId>-client-secret`; public clients declare no secret; and the Flux Kustomization applying the Secret is a real transitive `dependsOn` ancestor (`wait: true`) of the ones applying the import and the reconciler. A missing SOPS key is now unmergeable. |
| **Heal** | `client-secret-reconciler.yaml` — CronJob, every 15m, two passes | Compares each client's **stored** secret with the mounted `keycloak-realm-clients` value and PUTs the **minimal** `{clientId, secret}` representation only where they differ; a second, independent pass does the same for the client URLs against the generated `client-urls.yaml` (see below). Skips correct clients, never logs a secret, holds a hard endpoint allow-list so users/groups/roles/flows are unreachable, and needs no Kubernetes API access (`automountServiceAccountToken: false`). |
| **Detect** | `conformance/tests/l2-behavioral/keycloak-client-secrets-match-git` + alerts `KeycloakClientSecretReconcilerFailing` / `…Stale` | Runs the same script in read-only `--audit` mode against the live realm and fails on any mismatch, literal placeholder **or drifted client URL**; the alerts make the reconciler's silence observable in prod. |

The reconciler's own `--selftest` (run by the L0 gate, which extracts the script from the shipped
ConfigMap) proves compare-then-write, **idempotence** (zero writes on a converged realm),
no-secret-logging, the endpoint allow-list, and fail-closed behaviour.

**Manual repair / one-off run** (the CronJob normally does this):

```sh
kubectl -n keycloak create job --from=cronjob/keycloak-client-secret-reconciler kc-fix-$(date +%s)
kubectl -n keycloak logs -l app.kubernetes.io/name=keycloak-client-secret-reconciler --tail=-1
```

## Client URLs: the same one-shot failure, one field over

Moving an environment's `BASE_DOMAIN` re-renders every declared `redirectUris` / `webOrigins` /
`rootUrl` / `baseUrl` / `adminUrl` in git — and reaches the realm **never**, because a completed
import does not re-run. Measured on prod: stored redirect URIs still on the pre-migration hostname
while git declared the new one. Every OIDC login then fails with a `redirect_uri` mismatch, the
`KeycloakRealmImport` still reads `Done=True`, and nothing alerts.

**Pass 2 of the same CronJob** closes it. It was made a second pass of the existing reconciler rather
than a sibling CronJob for one decisive reason: **a URL write needs no new endpoint.** It is the same
minimal `PUT /admin/realms/<realm>/clients/<uuid>`, and the current URLs already come back in the
allow-listed client lookup — so the hard allow-list that makes `/users`, `/groups`, `/roles` and
`/authentication` unreachable is widened by *nothing*, and is preserved rather than re-declared in a
second copy. (The ConfigMap also carries exactly one script key by L0 contract, so a sibling would
have had to fork ~300 lines of safety-critical code the header explicitly forbids forking.)

**The desired state is generated, not authored.** `client-urls.yaml` is rendered from
`keycloak-realm-import.yaml` by `ci/render-keycloak-client-urls.py`, and the L0 gate runs that
renderer with `--check` on every merge, so the committed file cannot disagree with the import. URL
strings are copied verbatim — a `${BASE_DOMAIN}` token passes through unchanged, and both files are
rendered by the **same** Flux Kustomization, so both are substituted in one pass with one value. The
renderer never parses a hostname and never reads `cluster-vars`: there is no second place the domain
can be decided.

```sh
# regenerate after editing a client URL in the realm import (the gate will demand it)
python3 ci/render-keycloak-client-urls.py --write
```

Properties, each proved by `--selftest` and each shown to be *falsifiable* by
`conformance/tests/l0-static/keycloak-client-secret-reconciler/mutations.py`:

* **Converged ⇒ zero writes.** List fields compare order-insensitively (`sorted`, not `set` —
  duplicates are still drift), because Keycloak does not preserve the authored order of
  `redirectUris`; an order-sensitive compare would rewrite every client forever while reporting
  success.
* **Gaining and losing a URI both work.** The declared list is exact, so a URI removed from git is
  removed from the realm — a stale wildcard left behind quietly widens what the realm will redirect
  to.
* **Undeclared ⇒ unmanaged.** A field the desired state omits is left exactly as it is. Absence never
  means "force to empty".
* **Public clients' URLs *are* managed** (their secrets are not): `kubernetes` is PKCE-public and its
  localhost callbacks are what `kubectl` logins land on.
* **The two passes are independent.** Each reads its own desired state and fails closed for its own
  fields only. A malformed URL ConfigMap cannot stop client-*secret* repair, and an unmounted Secret
  cannot stop URL repair.
* URLs are logged in full (they are public hostnames, and the before/after is what makes a migration
  auditable); secrets are still never logged.

**What the reconciler does NOT fix:** anything outside client secrets and those five URL fields. A
NEW client, a new protocol mapper or a changed scope still needs the realm import to actually re-run
(it will not on its own) or a deliberate admin-API/`kcadm` change. `Done=True` is never evidence that
a realm edit landed.

## Exceptions that keep native auth (do not force SSO) — ADR-0014

Plex/Seerr (Plex auth), Minecraft (Mojang/Microsoft), UniFi (native).