Add Grafana dashboard for Tailscale K8s operator monitoring

This commit adds a Grafana dashboard for monitoring Tailscale health, connectivity, and performance in Kubernetes environments. The dashboard provides visibility into subnet routers, health messages, and network traffic for Tailscale proxies deployed by the Kubernetes operator.

Signed-off-by: Raj Singh <raj@tailscale.com>

cmd/k8s-operator/deploy/chart/templates/grafana-dashboard.yaml

@@ -0,0 +1,18 @@
+{{- if .Values.grafanaDashboard.enabled }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ .Release.Name }}-grafana-dashboard
+  namespace: {{ .Release.Namespace }}
+  labels:
+    {{- with .Values.grafanaDashboard.labels }}
+    {{- toYaml . | nindent 4 }}
+    {{- end }}
+  annotations:
+    {{- with .Values.grafanaDashboard.annotations }}
+    {{- toYaml . | nindent 4 }}
+    {{- end }}
+data:
+  tailscale.json: |-
+{{ .Files.Get "monitoring/tailscale-dashboard.json" | indent 4 }}
+{{- end }} 

cmd/k8s-operator/deploy/chart/values.yaml

@@ -29,6 +29,16 @@ oauthSecretVolume: {}
 # https://helm.sh/docs/chart_best_practices/custom_resource_definitions/
 installCRDs: true
 
+# Grafana dashboard configuration
+grafanaDashboard:
+  enabled: false
+  # Labels to be added to the ConfigMap
+  labels:
+    grafana_dashboard: "1"
+  # Annotations to be added to the ConfigMap
+  annotations:
+    grafana_folder: "Tailscale"
+
 operatorConfig:
   # ACL tag that operator will be tagged with. Operator must be made owner of
   # these tags