Deploying the DNS Cluster Add-on

In this lab you will deploy the DNS add-on which provides DNS based service discovery to applications running inside the Kubernetes cluster.

The DNS Cluster Add-on

Deploy the kube-dns cluster add-on:

  1. kubectl create -f https://storage.googleapis.com/kubernetes-the-hard-way/kube-dns.yaml

output

  1. serviceaccount "kube-dns" created
  2. configmap "kube-dns" created
  3. service "kube-dns" created
  4. deployment "kube-dns" created

List the pods created by the kube-dns deployment:

  1. kubectl get pods -l k8s-app=kube-dns -n kube-system

output

  1. NAME                        READY     STATUS    RESTARTS   AGE
  2. kube-dns-3097350089-gq015   3/3       Running   0          20s
  3. kube-dns-3097350089-q64qc   3/3       Running   0          20s

Verification

Create a busybox deployment:

  1. kubectl run busybox --image=busybox --command -- sleep 3600

List the pod created by the busybox deployment:

  1. kubectl get pods -l run=busybox

output

  1. NAME                       READY     STATUS    RESTARTS   AGE
  2. busybox-2125412808-mt2vb   1/1       Running   0          15s

Retrieve the full name of the busybox pod:

  1. POD_NAME=$(kubectl get pods -l run=busybox -o jsonpath="{.items[0].metadata.name}")

Execute a DNS lookup for the kubernetes service inside the busybox pod:

  1. kubectl exec -ti $POD_NAME -- nslookup kubernetes

output

  1. Server:    10.32.0.10
  2. Address 1: 10.32.0.10 kube-dns.kube-system.svc.cluster.local
  4. Name:      kubernetes
  5. Address 1: 10.32.0.1 kubernetes.default.svc.cluster.local

Next: Smoke Test