fix(keycloak): readiness could not fail on the database, and the measured budget

Two corrections found while verifying the first CI run, not from the plan.

THE DEFAULT THAT MADE THE READINESS PROBE TOOTHLESS. Keycloak's DATABASE health
check is the one row of upstream's "Available Checks" table whose "Requires
Metrics" column says yes; Cluster, Graceful shutdown and Keycloak Initialized
say no. So with metrics-enabled=false - this chart's default until now -
/health/ready answers 200 while the database is gone, and the pod keeps taking
logins it cannot serve. The probe path was right and the aggregate behind it
contained nothing external, which is the urlaubsverwaltung defect (#218) in a
new hiding place: not a health group this time, but an option named for
observability, where nobody looks when reviewing a probe.

keycloak.metrics.enabled therefore defaults to TRUE, and its comment argues
about readiness rather than about scraping. The price is stated at the value:
/metrics then answers on the management port, unauthenticated, carrying realm
names, client ids and login counters - on a port that is ClusterIP-only and in
no Ingress. Switching it off is now documented as a decision about whether
readiness can fail at all. The CI fixture keeps it on and says why, so a green
run really does touch the database.

THE STARTUP BUDGET NOW CARRIES ITS MEASUREMENT. From the install-test of PR #87
on the Gitea docker runner (k3s v1.35.5, two replicas, empty database, image
pulled during the run): 71.8 seconds from `helm install` to BOTH pods Ready -
first at ~70.8s, second one second later, 0 restarts. The 600s budget stays,
with the reason for the headroom written down: everything in that run was the
cheap case, and a first install against a real database serializes the second
replica behind the first's Liquibase migration lock instead of letting it
arrive a second later.

AND AN OVERCLAIM OF MY OWN, REMOVED. ci/keycloak/test-values.yaml said a green
run proves jdbc-ping found the second replica. It does not: readiness reports
one node's own health, so a node that never found its peer is Ready, healthy
and alone - and two such nodes are two islands that each believe they are the
cluster. What the test does rule out is the louder half, a replica that cannot
start or cannot share the database. The Infinispan view has to be read out of
the log, which is what step 2 of NOTES.txt tells the operator to do, now with
the note that no probe and no install-test replaces that step. Measurement
point 4 of the plan therefore stays open.

Part of #83

README.md

@@ -22,7 +22,7 @@ Every chart has a wiki page of its own — `https://git.jk-dev.de/jlab-cluster/h
 | `garage` | Garage (S3-compatible object store) | **One** node, `replication_factor = 1` — a deliberate trade with its price named (Gitea #81): the volume layer underneath already replicates and encrypts, so Garage replication on top would be nine times the raw data across two layers that know nothing about each other. What that costs is that the factor applies to the **metadata** too, where a corrupted database is upstream-documented as "generally not recoverable" and a replicated volume replicates the corruption. Hence three settings that are mandatory rather than optional: `metadata_fsync = true` (**off** in Garage's defaults), the automatic metadata snapshots, and those snapshots on a **second PVC** — a file-system snapshot of a live metadata database is not a restore point, so the volume backup covers the blocks and not the index. The first PVC carries `metadata_dir` **and** `data_dir` as two subdirectories, because volume snapshots are atomic per volume: that is what keeps index and blocks consistent with each other. Two further properties shape the whole chart: the image is **`FROM scratch`** and contains exactly one file, `/garage` — no shell, so **exec probes are impossible here** and an init container would need a second image — and the RPC secret has to arrive as an **environment variable**, because `rpc_secret_file` rejects any file with a group bit set while the kubelet sets one (the reasoning sits at the value). Started with `garage server --single-node`, which creates the cluster layout in-process before any listener opens and is idempotent on the layout version, and with `--default-access-key`/`--default-bucket`, which **import** key and bucket from the 1Password item — so the vault is the source of truth instead of a copy of what the server generated. Readiness is the admin API's `/health`, liveness and startup deliberately are **not**: `/health` answers 503 until a layout exists, so a node waiting for one would be restarted forever |
 | `gotenberg` | Gotenberg | Deployment + Service only (no ingress) |
 | `homeassistant` | Home Assistant | StatefulSet; the only chart carrying Helm tests (`templates/tests/`) |
-| `keycloak` | Keycloak (OpenID Connect / SAML identity provider) | **Two** replicas with `cache=ispn`, clustered through Keycloak's default `jdbc-ping` stack — discovery runs over the PostgreSQL that is there anyway, so no headless Service and no JGroups wiring. Deployment, **no PVC** (Keycloak 26 keeps everything in the database, user sessions included). **The chart has two init containers and needs both** (Gitea #83): `db`, `health-enabled` and `metrics-enabled` are Keycloak *build* options, the published image is built with their defaults, and a runtime change makes Keycloak rewrite `/opt/keycloak/lib/quarkus` at start — which `readOnlyRootFilesystem: true` forbids and which upstream describes as a start that "creates an image that is mutable". An empty `emptyDir` over that path does not work either, because `QuarkusEntryPoint` loads `quarkus/quarkus-application.dat` before it dispatches any command, `build` included. So one init container **seeds** the directory into a volume, the next runs `kc.sh build` into it, and the serving container runs `start --optimized` — every container keeping the full hardening baseline. Build options therefore exist in exactly **one** place and a build option in `keycloak.env` fails the render. First chart with a `PodDisruptionBudget` (§11) and first `quay.io` image (hence the entry in `ci/trivy/data/ksv0125.yaml`). Two Services (8080, and the management port 9000 **never** published — it serves `/health/*` and optionally `/metrics` unauthenticated) and two Ingresses. **The admin hostname is not an access control**: `hostname-admin` only decides which URLs the server generates, and upstream states that it "does not prevent accessing the Administration REST API endpoints via the frontend URL" — restricting that API is reverse-proxy work, and the chart renders no `/admin` deny rule. `ingress.domain` is read as `KC_HOSTNAME` (as a full URL, which upstream requires alongside `hostname-admin`), so it stays required with the Ingress off. Liveness is `/health/live` and deliberately not `/health` or `/health/ready` — those include the database, and a liveness probe on them restarts the whole cluster for as long as the database is away. Two traps at the values: upstream's `db-pool-max-size` default of 100 would ask a default PostgreSQL for 200 connections across two replicas (the chart ships 20), and two releases sharing one database **merge into one Infinispan cluster** unless the cluster names differ |
+| `keycloak` | Keycloak (OpenID Connect / SAML identity provider) | **Two** replicas with `cache=ispn`, clustered through Keycloak's default `jdbc-ping` stack — discovery runs over the PostgreSQL that is there anyway, so no headless Service and no JGroups wiring. Deployment, **no PVC** (Keycloak 26 keeps everything in the database, user sessions included). **The chart has two init containers and needs both** (Gitea #83): `db`, `health-enabled` and `metrics-enabled` are Keycloak *build* options, the published image is built with their defaults, and a runtime change makes Keycloak rewrite `/opt/keycloak/lib/quarkus` at start — which `readOnlyRootFilesystem: true` forbids and which upstream describes as a start that "creates an image that is mutable". An empty `emptyDir` over that path does not work either, because `QuarkusEntryPoint` loads `quarkus/quarkus-application.dat` before it dispatches any command, `build` included. So one init container **seeds** the directory into a volume, the next runs `kc.sh build` into it, and the serving container runs `start --optimized` — every container keeping the full hardening baseline. Build options therefore exist in exactly **one** place and a build option in `keycloak.env` fails the render. First chart with a `PodDisruptionBudget` (§11) and first `quay.io` image (hence the entry in `ci/trivy/data/ksv0125.yaml`). Two Services (8080, and the management port 9000 **never** published — it serves `/health/*` and optionally `/metrics` unauthenticated) and two Ingresses. **The admin hostname is not an access control**: `hostname-admin` only decides which URLs the server generates, and upstream states that it "does not prevent accessing the Administration REST API endpoints via the frontend URL" — restricting that API is reverse-proxy work, and the chart renders no `/admin` deny rule. `ingress.domain` is read as `KC_HOSTNAME` (as a full URL, which upstream requires alongside `hostname-admin`), so it stays required with the Ingress off. Liveness is `/health/live` and deliberately not `/health` or `/health/ready` — those include the database, and a liveness probe on them restarts the whole cluster for as long as the database is away. **`keycloak.metrics.enabled` defaults to `true` for the readiness probe, not for the metrics**: upstream's table of health checks carries a "Requires Metrics" column and the *database* check is the row that says yes, so with it off `/health/ready` answers 200 while the database is gone — the `urlaubsverwaltung` shape (#218) with the dependency hidden behind an option whose name says observability. Two traps at the values: upstream's `db-pool-max-size` default of 100 would ask a default PostgreSQL for 200 connections across two replicas (the chart ships 20), and two releases sharing one database **merge into one Infinispan cluster** unless the cluster names differ |
 | `matrix-synapse` | Matrix Synapse | StatefulSet plus an nginx delegation Deployment/Service |
 | `minecraft-router` | itzg/mc-router | Deployment + routing ConfigMap + NodePort Service (TCP only, no ingress); `mappings` is a required value |
 | `minecraft-server` | itzg/minecraft-server | StatefulSet + PVC + Service + init-script ConfigMap (no ingress); service type is a value (`ClusterIP` by default, routed via `minecraft-router`). **Only the newest Java line is maintained** (chart 5.0.0, #158): the directory carries one line, older ones stay published as frozen artifacts (java8/java17 at `4.0.0`, java21 at `4.1.0`) and receive no further chart changes — publishing once per line out of one directory is what made the lines drift. To run an older JVM with the current chart, set `image.tagOverride`; the chart then checks that `minecraft.version` fits the Java line of the **effective** tag and fails the render with both values named. Two cases pass unchecked on purpose: a tag without a `java<N>` part and a `minecraft.version` that is not a plain numeric `x[.y[.z]]`. `image.tagOverride` is deliberately outside Renovate's reach — `renovate.json5` tracks `appVersion` only. Since chart 2.0.0 the tag is an **immutable dated upstream release** (`appVersion: <release>-java8` / `-java17` / `-java21` / `-java25`, e.g. `2026.8.2-java8`) instead of the continuously rebuilt rolling line tag. Pilot for the strict `values.schema.json` (#68), which is now binding for every chart |