feat(metrics): CoreDNS service monitor

!1

templates/ServiceMonitor-CoreDNS.yaml

@@ -0,0 +1,28 @@
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app.kubernetes.io/name: coredns
+    app.kubernetes.io/part-of: {{ $.Chart.Name }}
+    app.kubernetes.io/version: {{ $.Chart.Version }}
+    app.kubernetes.io/managed-by: {{ $.Release.Service }}
+  name: coredns
+  namespace: monitoring
+spec:
+  endpoints:
+  - bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
+    interval: 15s
+    metricRelabelings:
+    - action: drop
+      regex: coredns_cache_misses_total
+      sourceLabels:
+      - __name__
+    port: metrics
+  jobLabel: app.kubernetes.io/name
+  namespaceSelector:
+    matchNames:
+    - kube-system
+  selector:
+    matchLabels:
+      k8s-app: kube-dns