Add VMPodScrape for authentik-server metrics (#476)

Authentik server pods expose django_prometheus metrics on :9300, but only ldap-outpost and redis-exporter are scraped in this namespace. Add the missing per-app scrape.

- add apps/base/authentik/server-vmpodscrape.yaml selecting app.kubernetes.io/name=authentik, component=server on the metrics port
- wire it into apps/base/authentik/kustomization.yaml

Reviewed-on: #476
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/authentik/kustomization.yaml

@@ -19,6 +19,7 @@ resources:
   - redis-deployment.yaml
   - redis-pvc.yaml
   - redis-service.yaml
+  - server-vmpodscrape.yaml
   - vaultauth.yaml
   - vaultstaticsecret.yaml
   - vmpodscrape.yaml

apps/base/authentik/server-vmpodscrape.yaml

@@ -0,0 +1,16 @@
+---
+# Scrape the authentik server's django_prometheus endpoint (:9300). Picked up
+# by the observability VMAgent (selectAllByDefault).
+apiVersion: operator.victoriametrics.com/v1beta1
+kind: VMPodScrape
+metadata:
+  name: authentik-server
+  namespace: authentik
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: authentik
+      app.kubernetes.io/component: server
+  podMetricsEndpoints:
+    - port: metrics
+      path: /metrics