Add pods DNS resolution for external names

deployments/coredns.yaml

@@ -61,6 +61,7 @@ data:
           fallthrough in-addr.arpa ip6.arpa
         }
         prometheus :9153
+        forward . /etc/resolv.conf
         cache 30
         loop
         reload

docs/09-bootstrapping-kubernetes-workers.md

@@ -35,7 +35,7 @@ Verify if swap is enabled:
 sudo swapon --show
 ```
 
-If output is empthy then swap is not enabled. If swap is enabled run the following command to disable swap immediately:
+If output is empty then swap is not enabled. If swap is enabled run the following command to disable swap immediately:
 
 ```bash
 sudo swapoff -a

docs/12-dns-addon.md

@@ -4,10 +4,22 @@ In this lab you will deploy the [DNS add-on](https://kubernetes.io/docs/concepts
 
 ## The DNS Cluster Add-on
 
+Get the CoreDNS yaml:
+
+```bash
+wget https://storage.googleapis.com/kubernetes-the-hard-way/coredns.yaml
+```
+
+Edit the `coredns.yaml` file to change CoreDNS configuration to enable DNS resolution for external name:
+
+```bash
+sed '/.*prometheus :9153/a \ \ \ \ \ \ \ \ forward . /etc/resolv.conf' coredns.yaml
+```
+
 Deploy the `coredns` cluster add-on:
 
 ```bash
-kubectl apply -f https://storage.googleapis.com/kubernetes-the-hard-way/coredns.yaml
+kubectl apply -f coredns.yaml
 ```
 
 > Output: