Kubernetes services

A Kubernetes service is an abstraction which defines a logical set of Pods and a policy by which to access. When you create a Service, it creates a corresponding DNS entry.

• https://kubernetes.io/docs/concepts/services-networking/service/
• kind: Service
  • spec.type:ClusterIP, LoadBalancer, NodePort, ExternalName

kubectl -n nginx-ingress get svc
NAME            TYPE           CLUSTER-IP      EXTERNAL-IP                              PORT(S)                               
AGE
nginx-ingress   LoadBalancer   10.100.100.2   xxxx70yyyy.us-west-1.elb.amazonaws.com    80:31982/TCP,443:30529/TCP            8d

Commands

• kubectl create clusterip
• kubectl create service loadbalancer
• kubectl create nodeport
• kubectl create service externalname
• kubectl get service

Example

Kubernetes sample service: my-service

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app: MyAppLabel
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376

If targetPort is not specified then same port value is used also as targetPort

Changelog

• v1.31 (Aug 2024) K8s traffic distribution for Services
• v1.18 (March 2020) AppProtocol is a new optional field on ports in Endpoints and Services

Related terms

• kubectl get services
• kubectl get svc: CLUSTER-IP EXTERNAL-IP
• kubectl delete services hello-minikube
• Deployments
• ConfigMaps
• kubectl port-forward
• Kubernetes Endpoints: kind: Endpoint
• kind: ReplicaSet
• kubectl expose
• Kubernetes headless service
• Terraform resource: kubernetes_service
• Kubernetes events
• service.beta.kubernetes.io
• service.externalTrafficPolicy=Cluster

Activities

• Review CKA 1.23: 20% - Service & Networking
• Review CKA v1.18: Understand Services and other network primitives
• Review CKA v1.15: Understand Services

See also

• Kubernetes services (kind: service), kubectl get services, kubectl describe service, kubectl create service [ loadbalancer | nodeport | clusterip | externalname ], kubectl expose, headless service, service.beta.kubernetes.io