add authentication lab

docs/09-dns-addon.md

@@ -0,0 +1,41 @@
+# 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
+
+### 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-v19-965658604-c8g5d   3/3       Running   0          49s
+kube-dns-v19-965658604-zwl3g   3/3       Running   0          49s
+```