CKAD field manual

k8s Service YAML example

A Service load-balances to Pods whose labels match selector. port is the Service, targetPort is the container.

Create

kubectl expose deploy/web --name=web --port=80 --target-port=80
kubectl expose po/web --name=web --port=80 --target-port=80 --type=NodePort

ClusterIP

apiVersion: v1
kind: Service
metadata:
  name: web
  namespace: default
spec:
  type: ClusterIP
  selector:
    app: web
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 80

NodePort

apiVersion: v1
kind: Service
metadata:
  name: web
spec:
  type: NodePort
  selector:
    app: web
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30080

Headless

spec:
  clusterIP: None
  selector:
    app: web
  ports:
    - port: 80
      targetPort: 80

Inspect

kubectl get svc,ep web
kubectl describe svc web

Fields

selector: Matches Pod labels (template.metadata.labels). Not the Deployment name.
port: The Service port. Clients use this.
targetPort: The container port. Often the same number as port. Often not.
nodePort: Only on type NodePort or LoadBalancer.
clusterIP: None = headless. DNS returns Pod IPs.
kubectl expose: --port is the Service. --target-port is the container.

Watch

selector matches Pod labels (Deployment: template.metadata.labels), not the Deployment name.
port = Service. targetPort = container. nodePort only on NodePort / LoadBalancer.
Default type is ClusterIP. clusterIP: None is headless — DNS returns Pod IPs.

Official docs Services

Practice these objects on a live cluster →