v-m: Scrape metrics from Authelia

Authelia exposes Prometheus metrics from a different server socket,
which is not enabled by default.

authelia/authelia.yaml

@@ -66,6 +66,13 @@ spec:
           value: /run/authelia/secrets/oidc.hmac_secret
         - name: AUTHELIA_IDENTITY_PROVIDERS_OIDC_ISSUER_PRIVATE_KEY_FILE
           value: /run/authelia/secrets/oidc.issuer_private_key
+        ports:
+        - containerPort: 9091
+          name: http
+          protocol: TCP
+        - containerPort: 9959
+          name: metrics
+          protocol: TCP
         startupProbe:
           httpGet:
             port: 9091

authelia/configuration.yml

@@ -157,3 +157,7 @@ storage:
     username: authelia.authelia
     tls:
       skip_verify: false
+
+telemetry:
+  metrics:
+    enabled: true

victoria-metrics/scrape.yml

@@ -359,3 +359,21 @@ scrape_configs:
     regex: '8008'
   - source_labels: [__meta_kubernetes_pod_name]
     target_label: instance
+
+- job_name: authelia
+  kubernetes_sd_configs:
+  - role: pod
+    namespaces:
+      names:
+      - authelia
+    selectors:
+    - role: pod
+      label: app.kubernetes.io/name=authelia
+  relabel_configs:
+  - action: keep
+    source_labels:
+    - __meta_kubernetes_pod_container_port_name
+    regex: metrics
+  - source_labels:
+    - __meta_kubernetes_pod_name
+    target_label: instance