feat(longhorn): Add monitoring to longhorn

This patch adds a service monitor for longhorn

infrastructure/longhorn/kustomization.yaml

@@ -11,6 +11,7 @@ resources:
   - https://git.shivering-isles.com/github-mirror/longhorn/longhorn/-/raw/v1.2.3/examples/network-policy/backing-image-manager-network-policy.yaml
   - https://git.shivering-isles.com/github-mirror/longhorn/longhorn/-/raw/v1.2.3/examples/network-policy/backing-image-data-source-network-policy.yaml
   - ../../shared/networkpolicies/allow-from-ingress.yaml
+  - ../../shared/networkpolicies/allow-from-monitoring.yaml
 patchesStrategicMerge:
   - networkpolicy.yaml
 

infrastructure/longhorn/networkpolicy.yaml

+---
 apiVersion: networking.k8s.io/v1
 kind: NetworkPolicy
 metadata:
@@ -6,3 +7,12 @@ spec:
   podSelector:
     matchLabels:
       app: longhorn-ui
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-from-monitoring
+spec:
+  podSelector:
+    matchLabels:
+      app: longhorn-manager

infrastructure/longhorn/servicemonitor.yaml

+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: longhorn-prometheus-servicemonitor
+  namespace: longhorn-system
+  labels:
+    name: longhorn-prometheus-servicemonitor
+spec:
+  selector:
+    matchLabels:
+      app: longhorn-manager
+  namespaceSelector:
+    matchNames:
+    - longhorn-system
+  endpoints:
+  - port: manager