kubernetes services

service
is an object just like pods, replica set or deployments that we worked with before, one of its use case it to listen to a port on the node and forward request on that port to a port on the pod.

service types:
1. node port
makes internal pod accessible on a port on the node
2. cluster ip
service creates a virtual ip inside the cluster to enable communication between different services, such as frontend servers to the backend servers
3. load balancer


How to create a service
it will be just like we created deployment replicaset

example:

kind: Service
apiVersion: v1
metadata:
  name: myapp-service
spec:
  type: NodePort
  ports:
    - targetPort: 80
      port: 80
      nodePort: 30008
  selector:
    app: myapp

ClusterIP:

A full stack application has a number of different kind of pods running, you may have a frontend pod, web server etc

These all need to communicate with each other
How to establish a connection between them. Since the pods can go down and new ones can spin up any time we just cannot rely on the IP. Also since there are many pods having these things running where to go to and who makes that decision.

Solution:
A service created for backend pods will help group backend pods and will group all backend pods together. The requests are forwards to one of the pods, under the service randomly.
This is what enables us to create and deploy a microservice based application on a kubernetes cluster.

The default type of service is ClusterIP.

targetport: is the port where backend is exposed
port: is the port where service is exposed, link service to a set of pods we use selector.