There are four types of Kubernetes services — ClusterIP, NodePort, LoadBalancer and ExternalName. The
type property under Spec helps to determines which service is exposed to the network.
ClusterIP is the most commonly used service type in Kubernetes. It is the default Kubernetes service.
We can define type as ClusterIP or leave blank in the service definition file when we need to configure our services as a ClusterIP.
Kubernetes will assign an internal IP to ClusterIP service. The scope of this service is with in the cluster only and it can’t be accessible directly from the outside of the Cluster. To expose these services to outside we need to use ingress controller.
apiVersion: v1 kind: Service metadata: name: "service-devops" spec: selector: app: devops type: ClusterIP ports: - protocol: TCP port: 80 targetPort: 80
Exposes the service on each Node’s IP at a static port (The NodePort). By using, you can access the NodePort service from outside the cluster.
apiVersion: v1 kind: Service metadata: name: my-nodeport-service spec: selector: app: my-app type: NodePort ports: - name: http port: 80 targetPort: 80 nodePort: 30036 protocol: TCP
Mainly, there are two differences between NodePort and ClusterIP service definition file. The first is, You need to be defined type as NodePort and an additional property NodePort need to be defined. If you don’t specify, then it will pick a random ports between 30000–32767.
A LoadBalancer service is the standard and easiest way of exposing a service to outside the cluster using a cloud provider’s load balancer. Each cloud providers (AWS, GCP, Azure, Digital Ocean etc.) has its own loadblance services which all the upcoming request routes to kubernetes services.
LoadBalancer service is an extension of NodePort service.
apiVersion: v1 kind: Service metadata: name: example-service spec: selector: app: example ports: - port: 8765 targetPort: 9376 type: LoadBalancer
Services with type ExternalName work as other kubernetes services, but when you want to access to that service name, instead of returning cluster-ip of this service, it returns CNAME record with value that mentioned in
externalName: parameter of service.
apiVersion: v1 kind: Service metadata: name: my-service spec: type: ExternalName externalName: my.database.example.com
An author, blogger and DevOps practitioner. In spare time, I loves to try out the latest open source technologies.