Services

Pods are ephemeral. When a Pod dies, its IP address is gone. A Service provides a single, stable IP address and DNS name for a set of Pods, acting as a load balancer.

1. ClusterIP (Default)

This is the most common type. It makes the Service reachable only inside the cluster.

service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: my-web-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: ClusterIP

Apply and Verify

Action:

kubectl apply -f service.yaml
kubectl get services

Result:

NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
my-web-service   ClusterIP   10.96.123.45    <none>        80/TCP    10s

(Now, any other Pod in the cluster can reach the nginx pods at http://my-web-service)

2. NodePort

Exposes the Service on a specific port (30000-32767) on each Node's IP. Use this for simple external access or on-premise clusters.

Action (Manifest snippet):

spec:
  type: NodePort
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30080

3. LoadBalancer

On cloud providers (AWS, GCP, Azure), this type creates a real Cloud Load Balancer with a public IP.

Check External IP

Action:

kubectl get svc my-lb-service

Result:

NAME            TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)        AGE
my-lb-service   LoadBalancer   10.96.0.1      35.200.12.34    80:31234/TCP   2m

(You can now visit http://35.200.12.34 in your browser!)

4. Headless Services

For stateful applications (like databases), you can set clusterIP: None. This returns all Pod IP addresses instead of one load-balanced IP.

Summary

• ClusterIP: Internal only (default).
• NodePort: External via NodeIP:Port.
• LoadBalancer: External via Cloud Provider's IP.
• Selectors: Link the Service to the correct Pods.