parts/k8s/addons/coredns.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
  labels:
      kubernetes.io/cluster-service: "true"
      addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: Reconcile
  name: system:coredns
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - services
  - pods
  - namespaces
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
- apiGroups:
  - discovery.k8s.io
  resources:
  - endpointslices
  verbs:
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: Reconcile
  name: system:coredns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:coredns
subjects:
- kind: ServiceAccount
  name: coredns
  namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
data:
  Corefile: |
    import conf.d/Corefile*
    .:53 {
        errors
        health {
          # this should be > readiness probe failure time
          lameduck 35s
        }
        ready
        kubernetes {{ContainerConfig "domain"}} in-addr.arpa ip6.arpa {
            pods insecure
            fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
        reload
        loadbalance
        import custom/*.override
    }
    import custom/*.server
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns-custom
  namespace: kube-system
  labels:
    addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    # Add custom CoreDNS configuration here.
    {{- /*
    See https://github.com/coredns/coredns/tree/master/plugin/azure for information
    about the Azure DNS plugin. */}}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: "CoreDNS"
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  {{- /* replicas: not specified here:
  1. In order to make Addon Manager do not reconcile this replicas parameter.
  2. Default is 1.
  3. Will be tuned in real time if DNS horizontal auto-scaling is turned on. */}}
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
    spec:
      priorityClassName: system-cluster-critical
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: k8s-app
                  operator: In
                  values:
                  - kube-dns
              topologyKey: topology.kubernetes.io/zone
            weight: 10
          - podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: k8s-app
                  operator: In
                  values:
                  - kube-dns
              topologyKey: kubernetes.io/hostname
            weight: 5
      serviceAccountName: coredns
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
          operator: "Exists"
        - key: node-role.kubernetes.io/control-plane
          effect: NoSchedule
          operator: "Exists"
        - key: CriticalAddonsOnly
          operator: "Exists"
        - operator: "Exists"
          effect: NoExecute
        - operator: "Exists"
          effect: NoSchedule
      nodeSelector:
        kubernetes.io/os: linux
        {{- if ContainerConfig "use-host-network"}}
        kubernetes.azure.com/role: agent
        {{end}}
      containers:
      - name: coredns
        image: {{ContainerImage "coredns"}}
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
          readOnly: true
        - mountPath: /etc/coredns/conf.d
          name: config-custom
          readOnly: true
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
          periodSeconds: 10
          timeoutSeconds: 1
          successThreshold: 1
          failureThreshold: 3
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
      dnsPolicy: Default
      {{- if ContainerConfig "use-host-network"}}
      hostNetwork: {{ContainerConfig "use-host-network"}}
      {{end}}
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile
        - name: config-custom
          configMap:
            name: coredns-custom
            items:
            - key: Corefile
              path: Corefile
            optional: true
---
apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: CoreDNS
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: {{ContainerConfig "clusterIP"}}
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP
  - name: metrics
    port: 9153
    protocol: TCP
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns-autoscaler
  namespace: kube-system
  labels:
    k8s-addon: coredns.addons.k8s.io
    addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    k8s-addon: coredns.addons.k8s.io
    addonmanager.kubernetes.io/mode: Reconcile
  name: coredns-autoscaler
rules:
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["list","watch"]
  - apiGroups: [""]
    resources: ["replicationcontrollers/scale"]
    verbs: ["get", "update"]
  - apiGroups: ["extensions", "apps"]
    resources: ["deployments/scale", "replicasets/scale"]
    verbs: ["get", "update"]
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["get", "create"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    k8s-addon: coredns.addons.k8s.io
    addonmanager.kubernetes.io/mode: Reconcile
  name: coredns-autoscaler
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: coredns-autoscaler
subjects:
- kind: ServiceAccount
  name: coredns-autoscaler
  namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coredns-autoscaler
  namespace: kube-system
  labels:
    k8s-app: coredns-autoscaler
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  selector:
    matchLabels:
      k8s-app: coredns-autoscaler
  template:
    metadata:
      labels:
        k8s-app: coredns-autoscaler
    spec:
      priorityClassName: system-cluster-critical
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
          operator: "Exists"
        - key: node-role.kubernetes.io/control-plane
          effect: NoSchedule
          operator: "Exists"
        - key: CriticalAddonsOnly
          operator: "Exists"
        - operator: "Exists"
          effect: NoExecute
        - operator: "Exists"
          effect: NoSchedule
      nodeSelector:
        kubernetes.io/os: linux
      containers:
      - name: autoscaler
        image: {{ContainerImage "coredns-autoscaler"}}
        resources:
          requests:
            cpu: 20m
            memory: 10Mi
        command:
        - /cluster-proportional-autoscaler
        - --namespace=kube-system
        - --configmap=coredns-autoscaler
        - --target=Deployment/coredns
        - --default-params={"linear":{"coresPerReplica":{{ContainerConfig "cores-per-replica"}},"nodesPerReplica":{{ContainerConfig "nodes-per-replica"}},"min":{{ContainerConfig "min-replicas"}}}}
        - --logtostderr=true
        - --v=2
      serviceAccount: coredns-autoscaler
      serviceAccountName: coredns-autoscaler