Jackett failed on 2026-09-30 in the most expensive way available: HTTP 200 and a
plausible page. oauth2-proxy answers an unauthenticated XHR with a 302 to Keycloak
rather than a 401; the browser follows it silently against a live SSO session and
the call resolves 200 carrying a 44 KB HTML dashboard where the app's JavaScript
wanted JSON. The user is never re-prompted, reloading never helps, and every uptime
check stays green. `jackett-down` watches replicas_available, which was 1 throughout.
The reason nothing alerted turns out not to be a missing rule. Measured on prod:
count by (__name__) ({__name__=~"oauth2_proxy.*"})
oauth2_proxy_requests_in_flight => 2
Two series, both from the SHARED forward-auth Deployment. The six per-app gate
sidecars (crafty, jackett, pihole, qbittorrent, radarr, sonarr) publish nothing at
all: no --metrics-address, so the metrics listener never starts; no `metrics`
container port; no ServiceMonitor or PodMonitor selects them. The alert the incident
calls for — sustained auth redirects to an authenticated user — is therefore NOT
WRITABLE, and writing it anyway would have shipped a rule that is present,
evaluating, permanently silent and indistinguishable from health.
So alert on the condition that made the incident invisible, from families that ARE
scraped:
OAuth2ProxyGateUnobserved
count by (namespace) (kube_pod_container_info{container="oauth2-proxy"})
unless
count by (namespace) (up{container="oauth2-proxy"})
kube_pod_container_info is kube-state-metrics (a declared scrape owner) and sees the
container whether or not it exports anything; `up` is UNIVERSAL and carries a
`container` label for any target, so the rule needs no advance knowledge of what job
name a future per-app scrape picks. Nothing in it touches oauth2_proxy_*, so it
cannot be inert for the reason it is reporting. Run verbatim against live prod it
returns six namespaces and correctly excludes oauth2-proxy. It clears per namespace
as each gate gains a real scrape.
Also:
- promtool companion test pinning all four states: fires unscraped, quiet when
scraped, honours for:1h, and STOPS once a scrape appears under a different job name.
- runbooks/oauth2-proxy-auth-failures.md — tell the gate's refusal from the group
check from the app's own login from an XHR that silently got HTML, with the
2026-09-30 jackett trace as the worked example and the Loki queries to use while
there are no metrics. Registered in the configMapGenerator and README.
- runbooks/README.md gains an inert-alerts row for the unscraped sidecars.
Rejected: an alert on the shared proxy's oauth2_proxy_requests_total ratio. It needs
a conformance/ SCRAPE_OWNERS entry (human approval) and, decisively, would not have
fired on this incident — the shared instance is not in any sidecar-gated app's data
path and its current pods have proxied nothing. It would have looked like coverage
and been none.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
oauth2-proxy is a leaf forward-auth service that depends on Keycloak +
trusted wildcard TLS + split-horizon DNS. It lived in the gating `platform`
Flux Kustomization (wait:true), so on a cold start it Failed until those
dependencies existed, keeping the whole `platform` tier not-Ready. That in
turn blocked `platform-config` — which brings up the very Keycloak instance,
wildcard Certificate and L2 VIP oauth2-proxy needs (and previously carried
oauth2-proxy's own httproute/servicemonitor) — from ever reconciling. A
self-gating cold-start deadlock, twice-proven (DECISIONS-LOG sessions 7 & 9).
Break the cycle by moving the whole oauth2-proxy component out of the
`platform` tier into its own non-gating post-platform Flux Kustomization:
- clusters/base/oauth2-proxy.yaml: new Kustomization -> ./platform/oauth2-proxy,
dependsOn platform-config, wait:false, substituteFrom cluster-vars.
- clusters/base/kustomization.yaml: reference the new Kustomization.
- platform/kustomization.yaml: drop the oauth2-proxy component (no longer in
the gating tier).
- platform/oauth2-proxy/kustomization.yaml: pull in httproute + servicemonitor
so the full component travels together.
- platform-config/kustomization.yaml: drop the in-place oauth2-proxy
httproute/servicemonitor refs (moved with the controller).
- clusters/dev/kustomization.yaml: add the SOPS decryption patch for the new
oauth2-proxy Kustomization (it now owns the encrypted credentials Secret that
the `platform` Kustomization used to decrypt).
Now `platform` reaches Ready without oauth2-proxy; platform-config brings up
Keycloak/TLS/DNS; then oauth2-proxy reconciles against dependencies that
already exist. wait:false guarantees its health can never gate anything above
it. No config of oauth2-proxy itself changed — only its reconciliation tier.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
Generate the 3 OIDC client secrets (SOPS-encrypted, minimal manifests) so the realm
import can inject the grafana + oauth2-proxy client secrets and both consumers match:
- platform/keycloak/keycloak-realm-clients.sops.yaml (grafana + oauth2-proxy client secrets)
- platform/oauth2-proxy/oauth2-proxy-credentials.sops.yaml (client-id/secret/cookie)
- platform/monitoring/grafana-oidc-credentials.sops.yaml (grafana client secret)
Wire each into its component kustomization and re-enable oauth2-proxy in platform +
platform-config (reverses the temp deferral now that its secret exists).
Values generated by PM per operator instruction (random; recorded out-of-repo at
~/.config/home-k3s/keycloak-sso-secrets.txt for later rotation). Encrypted via sops in the
dev container to the age recipient in .sops.yaml; plaintext never committed.
Serves: R-IDP-01, R-IDP-02, R-IDP-04, R-SEC-01.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
jakman85andClaude Opus 5