kubernetes-the-hard-way/docs/09-dns-addon.md

# Deploying the Cluster DNS Add-on

In this lab you will deploy the DNS add-on which is required for every Kubernetes cluster. Without the DNS add-on the following things will not work:

* DNS based service discovery 
* DNS lookups from containers running in pods

## Cluster DNS Add-on

```
kubectl create clusterrolebinding serviceaccounts-cluster-admin \
  --clusterrole=cluster-admin \
  --group=system:serviceaccounts
```

### Create the `kubedns` service:

```
kubectl create -f https://raw.githubusercontent.com/kelseyhightower/kubernetes-the-hard-way/master/services/kubedns.yaml
```

#### Verification

```
kubectl --namespace=kube-system get svc
```

```
NAME       CLUSTER-IP   EXTERNAL-IP   PORT(S)         AGE
kube-dns   10.32.0.10   <none>        53/UDP,53/TCP   5s
```

### Create the `kubedns` deployment:

```
kubectl create -f https://raw.githubusercontent.com/kelseyhightower/kubernetes-the-hard-way/master/deployments/kubedns.yaml
```

#### Verification

```
kubectl --namespace=kube-system get pods
```

```
NAME                       READY     STATUS    RESTARTS   AGE
kube-dns-321336704-6749s   4/4       Running   0          10s
```