Kubernetes NodePort vs LoadBalancer vs Ingress?

 ClusterIP

A ClusterIP service is the default Kubernetes service. It gives you a service inside your cluster that other apps inside your cluster can access. There is no external access.

The YAML for a ClusterIP service looks like this:

apiVersion: v1
kind: Service
metadata:  
  name: my-internal-service
spec:
  selector:    
    app: my-app
  type: ClusterIP
  ports:  
  - name: http
    port: 80
    targetPort: 80
    protocol: TCP

Start the Kubernetes Proxy:

$ kubectl proxy --port=8080

Now, you can navigate through the Kubernetes API to access this service using this scheme:

http://localhost:8080/api/v1/proxy/namespaces/<NAMESPACE>/services/<SERVICE-NAME>:<PORT-NAME>/

So to access the service we defined above, you could use the following address:

http://localhost:8080/api/v1/proxy/namespaces/default/services/my-internal-service:http/

NodePort

A NodePort service is the most primitive way to get external traffic directly to your service. NodePort, as the name implies, opens a specific port on all the Nodes (the VMs), and any traffic that is sent to this port is forwarded to the service.

The YAML for a NodePort service looks like this:

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

Basically, a NodePort service has two differences from a normal “ClusterIP” service. First, the type is “NodePort.” There is also an additional port called the nodePort that specifies which port to open on the nodes. If you don’t specify this port, it will pick a random port. 

** LoadBalancer **

A LoadBalancer service is the standard way to expose a service to the internet. On GKE, this will spin up a Network Load Balancer that will

 give you a single IP address that will forward all traffic to your service.

*** Ingress ***

Unlike all the above examples, Ingress is actually NOT a type of service. Instead, it sits in front of multiple services and act as a “smart router” or entrypoint into your cluster.

You can do a lot of different things with an Ingress, and there are many types of Ingress controllers that have different capabilities.

we called the below information to
" L7 HTTP Loadbalancer = ALB = Ingress " 

apiVersion: extensions/v1beta1

kind: Ingress

metadata:

  name: my-ingress

spec:

  backend:

    serviceName: other

    servicePort: 8080

  rules:

  - host: foo.mydomain.com

    http:

      paths:

      - backend:

          serviceName: foo

          servicePort: 8080

  - host: mydomain.com

    http:

      paths:

      - path: /bar/*

        backend:

          serviceName: bar

          servicePort: 8080