Services and service types — Kubernetes (K8s) & AKS

3. Services and service types

Basic★ Must knowLesson 3 of 15

Pods come and go with changing IPs; a Service gives a stable virtual IP and DNS name (shop-api.default.svc.cluster.local, or just shop-api in the same namespace) and load-balances to ready pods matching its selector.

Type	Exposes	Use
ClusterIP (default)	Internal virtual IP only	Service-to-service
NodePort	A port (30000–32767) on every node	Testing, legacy
LoadBalancer	Cloud load balancer with external IP	Expose a service directly (one LB per service)
ExternalName	DNS CNAME to an external host	Alias external services
Headless (`clusterIP: None`)	DNS returns pod IPs	StatefulSets, client-side discovery

yaml

apiVersion: v1
kind: Service
metadata: { name: shop-api }
spec:
  type: ClusterIP
  selector: { app: shop-api }
  ports:
    - port: 80          # service port
      targetPort: 8080  # container port