fix(obs): open 44180 to ns monitoring so the forward-auth gate sidecars are actually scrapable

platform/oauth2-proxy/podmonitor.yaml landed 2026-10-02 and discovered six targets that
have never once scraped. Measured on prod 2026-10-04: all six read health=down with
lastError "context deadline exceeded" and lastScrapeDuration exactly 10.0s — the
configured scrapeTimeout, i.e. packets DROPPED rather than refused.

Cause: every app namespace ships a default-deny NetworkPolicy with
policyTypes: [Ingress, Egress] and NO ingress key at all (deny-all-ingress), and the only
ingress allowance is <app>-allow-gateway-ingress: fromEntities: [ingress] -> 4180.
Prometheus matched no clause. Verified identical in all six of jackett, radarr, sonarr,
qbittorrent, pihole, crafty; zero namespaces had any -allow-monitoring-scrape object.

render.py already had the right idiom — r_monitoring_ingress_policy — but it returned None
unless the service declared observability.metricsEndpoint, and NO ServiceDefinition in this
catalog declares one. It was wired in at the call site and had never emitted a single
object on any branch: correct, and entirely latent.

It now also fires for the forward-auth gate sidecar's own metrics port, keyed on
_needs_oauth2_sidecar — deliberately the same condition the scrape keys on, since
podmonitor.yaml selects pods purely by the auth-mode label, so a target exists iff the
sidecar exists. Keying on observability.metrics instead would let metrics: false produce a
discovered-but-blocked target: the same "two halves authored apart" failure this function
exists to prevent.

Rendered here rather than in platform/oauth2-proxy because that tier would have to name app
namespaces created by the sibling apps-wave-0/1 tiers — it would apply on a running cluster
and fail on a cold bootstrap. podmonitor.yaml's header records that objection; rendering
per-app dissolves it.

Five CNPs result, one per forward-auth app, each opening only 44180 to only ns monitoring.
apps/ re-rendered with the invocation it was generated by (--no-image-automation, verified
byte-identical beforehand); --emit-waves deliberately not run, so no wave kustomization moved.

Three L1 goldens are regenerated with it (+63 lines, -0): a renderer change that adds an
object necessarily drifts the goldens that pin the renderer's output. The first gate run
caught container-workload-render and egress-class-render as FAIL with exactly this CNP as
the drift. default-deny-baseline-render's golden regenerated byte-identical, which is the
evidence that the regen is faithful and not a rubber stamp.

That puts conformance/** in the diff, which is a sensitive path: this PR needs a non-author
approving review. The local gate cannot see that — offline it reports approval-policy green
(N/A).

Local toolbox gate: rc 3 UNDETERMINED, not 0. Every stage that ran is green and l1 went
FAIL -> pass with the goldens; the only not-run stage is gitea-settings (no
GITEA_SETTINGS_TOKEN). L2/L3 conformance is UNVERIFIED for all 8 touched requirements.

Not verified: that the scrape now succeeds. Nothing is applied until Flux reconciles main.

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

catalog/render.py

@@ -1541,12 +1541,54 @@ def r_monitoring_ingress_policy(s: dict):
     trap Longhorn's own NetworkPolicies set (platform/longhorn/networkpolicy-metrics.yaml exists
     for exactly this reason), and it is a THIRD independent way for a metrics SLI to be inert.
 
-    Rendered only alongside a declared metricsEndpoint, and it opens ONLY that port to ONLY the
-    monitoring namespace: an allow for a port nothing serves would be a standing hole for no
+    Rendered only alongside a port something actually serves, and it opens ONLY that port to ONLY
+    the monitoring namespace: an allow for a port nothing serves would be a standing hole for no
     benefit.
+
+    TWO INDEPENDENT SOURCES OF A SERVED METRICS PORT, and this used to cover only the first:
+
+      1. `observability.metricsEndpoint` — the APP's own exporter. NOTE, measured 2026-10-04: no
+         ServiceDefinition in this catalog declares one, so before the sidecar clause below this
+         function had NEVER emitted a single object on any branch. It is correct but, so far,
+         entirely latent — do not read its presence as evidence that scrape ingress is solved.
+
+      2. THE forward-auth GATE SIDECAR's own `/metrics` on 44180 (added 2026-10-04). Every
+         `_needs_oauth2_sidecar` app gets `--metrics-address=0.0.0.0:{OAUTH2_PROXY_METRICS_PORT}`
+         and a named `metrics` container port from `_oauth2_sidecar_container`, so the port is
+         served whenever the sidecar exists — unconditionally, which is what makes it safe to
+         open without a per-app declaration.
+
+    WHY CLAUSE 2 KEYS ON `_needs_oauth2_sidecar` AND NOT ON `observability.metrics`: it must match
+    the condition the SCRAPE keys on, exactly. platform/oauth2-proxy/podmonitor.yaml selects pods
+    by the `homelab.keithjackson.dev/auth-mode: forward-auth` POD LABEL and nothing else, so a
+    target exists iff the sidecar exists. Keying the allowance on `observability.metrics` instead
+    would let `metrics: false` produce a discovered-but-blocked target — the same "two halves
+    authored apart" failure this function exists to prevent, just moved one field over.
+
+    THIS CLAUSE IS A BUG FIX, and the bug was live for 63.7h. Measured on prod 2026-10-04: all 6
+    sidecar targets across jackett/radarr/sonarr/qbittorrent/pihole read `health=down`,
+    `lastError: context deadline exceeded`, `lastScrapeDuration` exactly 10.0s — the scrapeTimeout,
+    i.e. packets DROPPED, not refused. Each app namespace ships a `default-deny` NetworkPolicy
+    with `policyTypes: [Ingress, Egress]` and NO `ingress` key at all (deny-all-ingress), and the
+    only ingress allowance is `<app>-allow-gateway-ingress`: `fromEntities: [ingress]` -> 4180.
+    Prometheus matched no clause. 5 x `TargetDown` + 6 x `OAuth2ProxyGateUnobserved` had been
+    re-notifying at ~22 emails/day since the PodMonitor landed on 2026-10-02.
+
+    WHY THE POLICY BELONGS HERE AND NOT IN platform/oauth2-proxy: podmonitor.yaml's header records
+    the objection — a policy in that tier would name app namespaces created by the SIBLING
+    apps-wave-0/1 tiers (measured Flux graph: `oauth2-proxy` and `apps-wave-0` both
+    `dependsOn=[platform-config]`, no ordering between them), so it would apply on a running
+    cluster and fail on a cold bootstrap. Rendered here it ships in the same tier that creates the
+    namespace, which dissolves that ordering problem entirely.
     """
-    ep = s["observability"].get("metricsEndpoint")
-    if not ep or not s["observability"]["metrics"]:
+    obs = s["observability"]
+    ep = obs.get("metricsEndpoint")
+    ports: list[str] = []
+    if ep and obs["metrics"]:
+        ports.append(str(ep["port"]))
+    if _needs_oauth2_sidecar(s):
+        ports.append(str(OAUTH2_PROXY_METRICS_PORT))
+    if not ports:
         return None
     return {
         "apiVersion": "cilium.io/v2",
@@ -1564,7 +1606,7 @@ def r_monitoring_ingress_policy(s: dict):
                         {"matchLabels": {"k8s:io.kubernetes.pod.namespace": MONITORING_NS}}
                     ],
                     "toPorts": [
-                        {"ports": [{"port": str(ep["port"]), "protocol": "TCP"}]}
+                        {"ports": [{"port": p, "protocol": "TCP"} for p in ports]}
                     ],
                 }
             ],