Skip to main content

Service vs Endpoint

Hands-on example​

Assume:

  • A working Kubernetes cluster
  • kubectl is configured

Initial state​

No Pods, Services, or Endpoints exist.

kubectl get pods
kubectl get svc
kubectl get endpoints
No resources found in default namespace.
No resources found in default namespace.
No resources found in default namespace.

Step 1: Create a Pod​

kubectl run demo --image=nginx --labels=app=demo
pod/demo created

Check Pod IP.

kubectl get pod demo -o wide
NAME   READY   STATUS    IP            NODE
demo   1/1     Running   10.244.0.10   node1

Step 2: Create a Service​

kubectl expose pod demo --port=80
service/demo exposed

Check Service.

kubectl get svc demo
NAME   TYPE        CLUSTER-IP     PORT(S)
demo   ClusterIP   10.96.40.21    80/TCP

Check Endpoints.

kubectl get endpoints demo
NAME   ENDPOINTS           AGE
demo   10.244.0.10:80      5s

What changed:

  • Endpoint was created pointing to the Pod IP

What did not change:

  • Pod IP stayed the same

Step 3: Make the Pod unready​

Delete the nginx index file.

kubectl exec demo -- rm /usr/share/nginx/html/index.html

Check Pod status.

kubectl get pod demo
NAME   READY   STATUS    RESTARTS   AGE
demo   0/1     Running   0          30s

Check Endpoints again.

kubectl get endpoints demo
NAME   ENDPOINTS   AGE
demo   <none>     30s

What changed:

  • Endpoint list is now empty

What did not change:

  • Service still exists
  • Pod still exists

Key observation​

  • Services are static definitions
  • Endpoints reflect current ready Pods