Service

---

• Service helps connect applications inside the cluster or to external users.
• Pods can die and new ones may be created with different IP addresses.
• Service provides a stable IP address and DNS name to access a group of Pods.
• It’s like a permanent door to access underlying pods

---

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: NodePort
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 80
      nodePort: 30007

---

• selector should have pods labels which needs to be exposed
• By default targetPort is set to the same value as the port field
• By default, Kubernetes control plane will allocate a nodePort from a range (default: 30000-32767) (optional)

---

Service Types

• Service types allow you to specify what kind of Service you want.

NodePort

• Service listens on a port on each Node and forwards the request to the Pod where our application is running.

ClusterIP

• Service creates a virtual IP inside the cluster to connect with other applications.

LoadBalancer

• Service provisions a LoadBalancer to expose our application externally in a cloud environment.

---

Commands

1. create a service

kubectl create -f service-definition.yml

2. get all services

kubectl get svc

3. describe service

kubectl describe svc <service-name>

4. expose a pods as a service

kubectl expose pod <pod-name> --port=80 --name <service-name> --type=NodePort

---

⬅️ Deployment | ConfigMaps ➡️

References

1. https://kubernetes.io/docs/concepts/services-networking/service/