Lab Solution Explore DNS optional

# set alias for convenience
alias k=kubectl

# list kube-system pods
k get pods -n kube-system

NAME                                  READY   STATUS    RESTARTS   AGE
coredns-74ff55c5b-9lcxv               1/1     Running   0          14m
coredns-74ff55c5b-kgtwz               1/1     Running   0          14m
etcd-controlplane                     1/1     Running   0          14m
kube-apiserver-controlplane           1/1     Running   0          14m
kube-controller-manager-controlplane  1/1     Running   0          14m
kube-flannel-ds-ztb5d                 1/1     Running   0          14m
kube-proxy-wq2p9                      1/1     Running   0          14m
kube-scheduler-controlplane           1/1     Running   0          14m

k get svc -n kube-system

NAME       TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)         AGE
kube-dns   ClusterIP   10.96.0.10    <none>        53/UDP,53/TCP   14m

k describe pod coredns-74ff55c5b-9lcxv -n kube-system

Containers:
  coredns:
    Image:         k8s.gcr.io/coredns:1.7.0
    Ports:         53/UDP, 53/TCP, 9153/TCP
    Args:
      -conf
      /etc/coredns/Corefile
    State:         Running
    Ready:         True
    Restart Count: 0
    Liveness:      http-get http://:8080/health delay=60s timeout=5s period=10s #success=1 #failure=5
    Readiness:     http-get http://:8181/ready delay=0s timeout=1s period=10s #success=1 #failure=3
    Mounts:
      /etc.coredns from config-volume (ro)
      /var/run/secrets/kubernetes.io/serviceaccount from coredns-token-8scbd (ro)

Volumes:
  config-volume:
    Type:       ConfigMap (a volume populated by a ConfigMap)
    Name:       coredns
    Optional:   false
  coredns-token-8scbd:
    Type:       Secret (a volume populated by a Secret)
    SecretName: coredns-token-8scbd
    Optional:   false