Create ExternalName Service¶

An ExternalName service is a type of service in kubernetes that allows you to create a service that simply points to an external service by its DNS name, rather than routing traffic to a set of pods.

Let's see this in action!

Step 1: Create ExternalName Service¶

Let's create an ExternalName service as follows:

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apiVersion: v1
kind: Service
metadata:
  name: my-externalname-service
spec:
  type: ExternalName
  externalName: google.com

Please note that we do not have selectors available for ExternalName services as they do not route traffic directly to pods but rather use an external DNS to resolve the service.

Let's apply the manifest to create the service:

kubectl apply -f my-externalname-service.yml

Step 2: Verify the Service¶

# List services
kubectl get svc

Note the EXTERNAL-IP field in the output. You'll see the external DNS the service resolves to.

Step 3: Access the Service¶

Let's see what happens when you access the service.

1. Create a simple pod that has ping Linux utility:

   kubectl run busybox --image=busybox --restart=Never -- /bin/sh -c "sleep 3600"
   

2. Start a shell session inside busybox container of the pod:

   kubectl exec -it busybox -- sh
   

3. Ping the service:

   ping my-externalname-service
   

You'll notice that it resolves to google.com which is the external DNS name configured for the service.

Clean Up¶

# Delete service
kubectl delete -f my-externalname-service.yml

# Delete busybox pod
kubectl delete pod busybox