Deploying kube-dns in a Kubernetes Cluster

You can deploy kube-dns to the cluster like so:

kubectl create -f https://raw.githubusercontent.com/ACloudGuru-Resources/kthw-lab-scripts/master/kube-dns.yaml

Verify that the kube-dns pod starts up correctly:

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

You should get output showing the kube-dns pod. It should look something like this:

NAME                        READY     STATUS    RESTARTS   AGE
kube-dns-598d7bf7d4-spbmj   3/3       Running   0          36s

Make sure that 3/3 containers are ready and that the pod has a status of Running. It may take a moment for the pod to be fully up and running, so if READY is not 3/3 at first, check again after a few moments.

Test the DNS by creating a service, and access the service from another pod using the service name.

Create a simple service like so:

kubectl run nginx --image=nginx

kubectl expose deployment nginx --port 80

Get a list of services:

kubectl get svc

You should see the nginx service listed.

Spin up a busybox pod for testing and get the pod name:

kubectl run busybox --image=busybox:1.28 --command -- sleep 3600

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

Perform a DNS lookup of the nginx service from within the busybox pod to verify that DNS is working:

kubectl exec $POD_NAME -- nslookup nginx

You should get output that looks like this:

Server:    10.32.0.10
Address 1: 10.32.0.10 kube-dns.kube-system.svc.cluster.local

Name:      nginx
Address 1: 10.32.0.248 nginx.default.svc.cluster.local