Kubernetes local core dns cache

nodelocaldns.yml

# Run kubelet with "--cluster-dns 169.254.20.10"
# In Kops we need to update the cluster spec:
#spec:
#  kubelet:
#    clusterDNS: 169.254.20.10
#
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: node-local-dns
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: node-local-dns
  namespace: kube-system
  labels:
    addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    cluster.local:53 {
      errors
      bind 169.254.20.10
      forward . 100.64.0.10 {
        force_tcp
      }
      cache {
        success 9984 30
        denial 9984 5
      }
      reload
      loop
      prometheus :9253
      health 169.254.20.10:8080
    }
    in-addr.arpa:53 {
      errors
      bind 169.254.20.10
      forward . 100.64.0.10 {
        force_tcp
      }
      cache 30
      reload
      loop
      prometheus :9253
    }
    ip6.arpa:53 {
      errors
      bind 169.254.20.10
      forward . 100.64.0.10 {
        force_tcp
      }
      cache 30
      reload
      loop
      prometheus :9253
    }
    .:53 {
      errors
      bind 169.254.20.10
      forward . /etc/resolv.conf
      cache 30
      reload
      prometheus :9253
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: node-local-dns
  namespace: kube-system
  labels:
    k8s-app: node-local-dns
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  updateStrategy:
    rollingUpdate:
      maxUnavailable: 10%
  selector:
    matchLabels:
      k8s-app: node-local-dns
  template:
    metadata:
       labels:
          k8s-app: node-local-dns
    spec:
      priorityClassName: system-node-critical
      serviceAccountName: node-local-dns
      hostNetwork: true
      dnsPolicy: Default  # Don't use cluster DNS.
      tolerations:
      - key: "CriticalAddonsOnly"
        operator: "Exists"
      - key: node-role.kubernetes.io/master
        operator: "Exists"
        effect: NoSchedule
      containers:
      - name: node-cache
        image: k8s.gcr.io/k8s-dns-node-cache:1.15.0
        resources:
          limits:
            memory: 30Mi
          requests:
            cpu: 25m
            memory: 5Mi
        args: [ "-localip", "169.254.20.10", "-conf", "/etc/coredns/Corefile" ]
        securityContext:
          privileged: true
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9253
          name: metrics
          protocol: TCP
        - containerPort: 6060
          name: pprof
          protocol: TCP
        livenessProbe:
          httpGet:
            host: 169.254.20.10
            path: /health
            port: 8080
          initialDelaySeconds: 60
          timeoutSeconds: 5
        volumeMounts:
        - mountPath: /run/xtables.lock
          name: xtables-lock
          readOnly: false
        - name: config-volume
          mountPath: /etc/coredns
      volumes:
      - name: xtables-lock
        hostPath:
          path: /run/xtables.lock
          type: FileOrCreate
      - name: config-volume
        configMap:
          name: node-local-dns
          items:
            - key: Corefile
              path: Corefile