kubespray/roles/kubernetes-apps/ansible/templates/coredns-deployment.yml.j2

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: "coredns{{ coredns_ordinal_suffix }}"
  namespace: kube-system
  labels:
    k8s-app: "kube-dns{{ coredns_ordinal_suffix }}"
    addonmanager.kubernetes.io/mode: Reconcile
    kubernetes.io/name: "coredns{{ coredns_ordinal_suffix }}"
spec:
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 10%
  selector:
    matchLabels:
      k8s-app: kube-dns{{ coredns_ordinal_suffix }}
  template:
    metadata:
      labels:
        k8s-app: kube-dns{{ coredns_ordinal_suffix }}
      annotations:
        seccomp.security.alpha.kubernetes.io/pod: 'runtime/default'
    spec:
      priorityClassName: system-cluster-critical
      nodeSelector:
        kubernetes.io/os: linux
      serviceAccountName: coredns
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
        - key: node-role.kubernetes.io/control-plane
          effect: NoSchedule
{% if dns_extra_tolerations | default(None) %}
        {{ dns_extra_tolerations | list | to_nice_yaml(indent=2) | indent(8) }}
{% endif %}
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - topologyKey: "kubernetes.io/hostname"
            labelSelector:
              matchLabels:
                k8s-app: kube-dns{{ coredns_ordinal_suffix }}
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            preference:
              matchExpressions:
{% if kube_version is version('v1.20.0', '<') %}
              - key: node-role.kubernetes.io/master
{% else %}
              - key: node-role.kubernetes.io/control-plane
{% endif %}
                operator: In
                values:
                - ""
      containers:
      - name: coredns
        image: "{{ coredns_image_repo }}:{{ coredns_image_tag }}"
        imagePullPolicy: {{ k8s_image_pull_policy }}
        resources:
          # TODO: Set memory limits when we've profiled the container for large
          # clusters, then set request = limit to keep this container in
          # guaranteed class. Currently, this container falls into the
          # "burstable" category so the kubelet doesn't backoff from restarting it.
          limits:
            memory: {{ dns_memory_limit }}
          requests:
            cpu: {{ dns_cpu_requests }}
            memory: {{ dns_memory_requests }}
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 10
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile
{% if dns_etchosts | default(None) %}
            - key: hosts
              path: hosts
{% endif %}