add prometheus service monitor to coredns (#12003)

Signed-off-by: Ryan Belgrave <ryan.belgrave@optum.com>

stable/coredns/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: coredns
-version: 1.5.3
+version: 1.5.4
 appVersion: 1.5.0
 description: CoreDNS is a DNS server that chains plugins and provides Kubernetes DNS Services
 keywords:

stable/coredns/templates/monitor.yaml

@@ -0,0 +1,33 @@
+{{- if .Values.prometheus.monitor.enabled }}
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: {{ template "coredns.fullname" . }}
+  {{- if .Values.prometheus.monitor.namespace }}
+  namespace: {{ .Values.prometheus.monitor.namespace }}
+  {{- end }}
+  labels:
+    app.kubernetes.io/managed-by: {{ .Release.Service | quote }}
+    app.kubernetes.io/instance: {{ .Release.Name | quote }}
+    helm.sh/chart: "{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}"
+    {{- if .Values.isClusterService }}
+    k8s-app: {{ .Chart.Name | quote }}
+    kubernetes.io/cluster-service: "true"
+    kubernetes.io/name: "CoreDNS"
+    {{- end }}
+    app.kubernetes.io/name: {{ template "coredns.name" . }}
+    {{- if .Values.prometheus.monitor.additionalLabels }}
+{{ toYaml .Values.prometheus.monitor.additionalLabels | indent 4 }}
+    {{- end }}
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/instance: {{ .Release.Name | quote }}
+      {{- if .Values.isClusterService }}
+      k8s-app: {{ .Chart.Name | quote }}
+      {{- end }}
+      app.kubernetes.io/name: {{ template "coredns.name" . }}
+      app.kubernetes.io/component: metrics
+  endpoints:
+    - port: metrics
+{{- end }}

stable/coredns/templates/service-metrics.yaml

@@ -0,0 +1,30 @@
+{{- if .Values.prometheus.monitor.enabled }}
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ template "coredns.fullname" . }}-metrics
+  labels:
+    app.kubernetes.io/managed-by: {{ .Release.Service | quote }}
+    app.kubernetes.io/instance: {{ .Release.Name | quote }}
+    helm.sh/chart: "{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}"
+    {{- if .Values.isClusterService }}
+    k8s-app: {{ .Chart.Name | quote }}
+    kubernetes.io/cluster-service: "true"
+    kubernetes.io/name: "CoreDNS"
+    {{- end }}
+    app.kubernetes.io/name: {{ template "coredns.name" . }}
+    app.kubernetes.io/component: metrics
+  annotations:
+{{ toYaml .Values.service.annotations | indent 4 }}
+spec:
+  selector:
+    app.kubernetes.io/instance: {{ .Release.Name | quote }}
+    {{- if .Values.isClusterService }}
+    k8s-app: {{ .Chart.Name | quote }}
+    {{- end }}
+    app.kubernetes.io/name: {{ template "coredns.name" . }}
+  ports:
+  - name: metrics
+    port: 9153
+    targetPort: 9153
+{{- end }}

stable/coredns/values.yaml

@@ -19,6 +19,12 @@ resources:
 
 serviceType: "ClusterIP"
 
+prometheus:
+  monitor:
+    enabled: false
+    additionalLabels: {}
+    namespace: ""
+
 service:
 # clusterIP: ""
 # loadBalancerIP: ""