Onboard Plex to the k3s platform via ServiceDefinition (WS-APPS)

Add catalog/plex.yaml (kind: container) and its rendered apps/plex.yaml,
and wire apps/kustomization.yaml. Plex = docs/13 row 1, the catalog's
largest service; validates the public-exposure + config-on-Longhorn path.

- image plexinc/pms-docker (pinned recent stable tag), port 32400
- exposure: public at plex.home.keithjackson.dev; egress: internet
- auth: native (Plex accounts, not Keycloak — docs/13/15 exception)
- config PVC 20Gi on longhorn; off-cluster backup (daily-offcluster) as the
  longhorn tier forbids reacquirable under L0 (R-STATE-03)
- observability up-SLI; update channel stable

Bulk media (R-STATE-04) deferred: the `bulk` StorageClass is a documented
stub (OQ-2 unresolved, NFS CSI not installed) so a bulk PVC would leave the
pod Pending. Media mount omitted; attach once bulk provisions.

Traces: R-GITOPS-02, R-NET-01/02/05, R-STATE-01/02/03, R-TLS/R-DNS,
R-OBS-01, R-UPD-01/03, R-IDP-02, R-PLAT-02.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

apps/kustomization.yaml

@@ -7,3 +7,4 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
   - pihole.yaml
+  - plex.yaml

apps/plex.yaml

@@ -0,0 +1,188 @@
+---
+# Namespace (trust zone; default-deny + policies apply)
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: plex
+  labels:
+    homelab.keithjackson.dev/app-namespace: 'true'
+    gateway-access: shared
+  annotations:
+    homelab.keithjackson.dev/backup-policy: daily-offcluster
+---
+# Default-deny baseline (R-NET-01): deny all, allow only DNS
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny
+  namespace: plex
+  labels:
+    homelab.keithjackson.dev/baseline: default-deny
+spec:
+  podSelector: {}
+  policyTypes:
+  - Ingress
+  - Egress
+  ingress: []
+  egress:
+  - to:
+    - namespaceSelector:
+        matchLabels:
+          kubernetes.io/metadata.name: kube-system
+    ports:
+    - protocol: UDP
+      port: 53
+    - protocol: TCP
+      port: 53
+---
+# PVC plex-config (R-STATE)
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: plex-config
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  accessModes:
+  - ReadWriteOnce
+  storageClassName: longhorn
+  resources:
+    requests:
+      storage: 20Gi
+---
+# Deployment (R-PLAT-02)
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: plex
+        homelab.keithjackson.dev/egress-class: internet
+        homelab.keithjackson.dev/auth-mode: native
+    spec:
+      containers:
+      - name: plex
+        image: plexinc/pms-docker:1.41.3.9314-a0bfa8370
+        ports:
+        - containerPort: 32400
+        volumeMounts:
+        - name: config
+          mountPath: /data/config
+      volumes:
+      - name: config
+        persistentVolumeClaim:
+          claimName: plex-config
+---
+# Service
+apiVersion: v1
+kind: Service
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  selector:
+    app.kubernetes.io/name: plex
+  ports:
+  - name: port-32400
+    port: 32400
+    targetPort: 32400
+---
+# CiliumNetworkPolicy gateway-ingress allow (R-NET-01/02): plex-allow-gateway-ingress
+apiVersion: cilium.io/v2
+kind: CiliumNetworkPolicy
+metadata:
+  name: plex-allow-gateway-ingress
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  endpointSelector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  ingress:
+  - fromEntities:
+    - ingress
+    toPorts:
+    - ports:
+      - port: '32400'
+        protocol: TCP
+---
+# HTTPRoute plex-32400 (R-TLS/R-DNS)
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: plex-32400
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  parentRefs:
+  - name: shared
+    namespace: gateway
+    sectionName: https
+  hostnames:
+  - plex.home.keithjackson.dev
+  rules:
+  - matches:
+    - path:
+        type: PathPrefix
+        value: /
+    backendRefs:
+    - name: plex
+      port: 32400
+---
+# ServiceMonitor (R-OBS-01)
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    release: kube-prometheus-stack
+    app.kubernetes.io/name: plex
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  namespaceSelector:
+    matchNames:
+    - plex
+  endpoints:
+  - port: metrics
+    interval: 30s
+---
+# PrometheusRule SLI alerts (R-OBS-01)
+apiVersion: monitoring.coreos.com/v1
+kind: PrometheusRule
+metadata:
+  name: plex-slis
+  namespace: plex
+  labels:
+    release: kube-prometheus-stack
+    app.kubernetes.io/name: plex
+spec:
+  groups:
+  - name: plex.slis
+    rules:
+    - alert: plex-down
+      expr: up{job="plex"} == 0
+      for: 5m
+      labels:
+        severity: critical
+        service: plex
+      annotations:
+        summary: plex is down
+        description: 'plex has been unreachable for 5m (SLI: up).'