Container Security

How to create a Kubernetes Service

Maneesha Mariam

With the running application, we want to access one service. Let’s create a ClusterIP type of service. We can:

  • Create a yaml manifest for the service and apply it, or
  • Use the “kubectl expose” command creates a service without creating a yaml file.

Like all Kubernetes objects, services are defined in YAML or JSON. The YAML file consists of the following parts:

  • apiVersion: v*
  • kind: a service
  • metadata.name: name of the service, which is the DNS name of the Service at the time of creation.
  • spec.selector: the pods included in the Service. Here, any pod with the label app=user will be added to the service.
  • spec.ports: list of port configurations, includes the following data:
  1. protocol: the network protocol to use with the port
  2. port: the port that incoming traffic goes to
  3. targetPort: the port on the pod that traffic should be sent to

Now, we will look into an example of YAML file:

  • apiVersion: v2
  • kind: Service
  • metadata:
  • name: service-backend
  • spec:
  • ports: port: 4000
  • protocol: TCP
  • targetPort: 333
  • selector:
  • run: deployment-backend
  • type: ClusterIP

The service ‘service-backend’ will be created, and any pod in the cluster can access it on their port 333 via http://service-backend:4000, or at the cluster’s IP address using port 4000.

Kubernetes services can also be created using the ‘kubectl expose’ command, which does not require a YAML file. The same service can be created using the command:

kubectl expose deployment deployment-backend – – port=333- – target-port=4000 –name=service-backend

Once you’ve got the configuration complete, create the service in your cluster as below:

kubectl apply -f service.yaml

To check that your service is running, you can execute the following command:

kubectl get services

You can see your new service in the list of services returned by this command. You can now access your pods using the service.