apiVersion: v1
kind: ServiceAccount
metadata:
  name: cluster-dns
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: cluster-dns
rules:
  - apiGroups:
      - ""
    resources:
      - endpoints
      - services
      - pods
      - namespaces
    verbs:
      - list
      - watch
  - apiGroups:
      - discovery.k8s.io
    resources:
      - endpointslices
    verbs:
      - list
      - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: cluster-dns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-dns
subjects:
  - kind: ServiceAccount
    name: cluster-dns
    namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: dns-config
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
          pods insecure
          fallthrough in-addr.arpa ip6.arpa
        }
        hosts /etc/coredns/NodeHosts {
          ttl 60
          reload 15s
          fallthrough
        }
        prometheus :9153
        cache 30
        loop
        reload
        loadbalance
        import /etc/coredns/custom/*.override
        forward . /etc/resolv.conf
    }
    import /etc/coredns/custom/*.server
  NodeHosts: |
    10.210.99.194 ********-n100
    10.133.210.151 ********-opi5p
    10.149.70.251 ********-2697
    10.100.10.13 ********-y520
    10.151.204.207 ********-nas
---
apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: CoreDNS
spec:
  clusterIP: 10.97.104.110
  ports:
    - name: dns
      port: 53
      protocol: UDP
      targetPort: 53
    - name: dns-tcp
      port: 53
      protocol: TCP
      targetPort: 53
    - name: metrics
      port: 9153
      protocol: TCP
      targetPort: 9153
  selector:
    k8s-app: kube-dns
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: cluster-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: CoreDNS
spec:
  replicas: 2
  revisionHistoryLimit: 0
  selector:
    matchLabels:
      k8s-app: kube-dns
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      labels:
        k8s-app: kube-dns
    spec:
      containers:
        - name: coredns
          image: rancher/mirrored-coredns-coredns:1.15.0@sha256:0a9d8c8ddf34347eb59aad9a8784f0710de88d6d112726d11d271f9bc6daca26
          imagePullPolicy: IfNotPresent
          args:
            - -conf
            - /etc/coredns/Corefile
          ports:
            - containerPort: 53
              name: dns
              protocol: UDP
            - containerPort: 53
              name: dns-tcp
              protocol: TCP
            - containerPort: 9153
              name: metrics
              protocol: TCP
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /health
              port: 8080
              scheme: HTTP
            initialDelaySeconds: 60
            periodSeconds: 10
            timeoutSeconds: 1
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /ready
              port: 8181
              scheme: HTTP
            periodSeconds: 2
            timeoutSeconds: 1
          resources:
            limits:
              memory: 170Mi
            requests:
              cpu: 100m
              memory: 70Mi
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              add:
                - NET_BIND_SERVICE
              drop:
                - all
            readOnlyRootFilesystem: true
          volumeMounts:
            - mountPath: /etc/coredns
              name: config-volume
              readOnly: true
            - mountPath: /etc/coredns/custom
              name: custom-config-volume
              readOnly: true
      dnsPolicy: Default
      nodeSelector:
        kubernetes.io/os: linux
      priorityClassName: system-cluster-critical
      serviceAccountName: cluster-dns
      terminationGracePeriodSeconds: 30
      tolerations:
        - key: CriticalAddonsOnly
          operator: Exists
        - effect: NoSchedule
          key: node-role.kubernetes.io/control-plane
          operator: Exists
      topologySpreadConstraints:
        - labelSelector:
            matchLabels:
              k8s-app: kube-dns
          maxSkew: 1
          topologyKey: kubernetes.io/hostname
          whenUnsatisfiable: DoNotSchedule
        - labelSelector:
            matchLabels:
              k8s-app: kube-dns
          maxSkew: 1
          topologyKey: topology.kubernetes.io/zone
          whenUnsatisfiable: ScheduleAnyway
      volumes:
        - configMap:
            items:
              - key: Corefile
                path: Corefile
              - key: NodeHosts
                path: NodeHosts
            name: dns-config
          name: config-volume
        - configMap:
            name: coredns-custom
            optional: true
          name: custom-config-volume
---
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: cluster-dns
  namespace: kube-system
spec:
  minAvailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns