Service NodePort

Applications running in a Kubernetes cluster find and communicate with each other, and the outside world, through the Service abstraction

We are using a Nginx webserver that echoes back the source IP of requests it receives through an HTTP header.

1. Create a Nginx WebServer with echoserver Image

kubectl create deployment web-app --image=k8s.gcr.io/echoserver:1.4

1. Expose the echoserver Image pod with the help of a service.

kubectl expose deployment web-app --name=web-app-svc --port=80 --target-port=8080 --type=NodePort

1. Get the Service IP Address

kubectl get svc web-app-svc

1. Run a Client Server to test NodePort Connectivity

kubectl run busybox -it --image=busybox --restart=Never --rm

Inside the Busy Box Image, we are going to run the below commands.

1. Check the IP Address of the Client.

ip addr

1. Use Wget to call the Web-app-svc from the Busybox Pod

Replace "10.0.170.92" with the IPv4 address of the Kubernetes Worker Node and Port which is in 30000 range.

wget -qO - 10.0.170.92:30171

If you observe the output has "client_address"

The client_address is not always the client pod's IP address. there a natting done, when it is sent to Destination.

Cleanup

1. Delete Service and Deployment

kubectl delete svc web-app-svc

kubectl delete deployment web-app