I have GKE to create a Kubernetes cluster, which is having 2 nodes and i have created a deployment to download nginx image with 2 replicas. Now that i have nginx images running on the same node ( NODE 1 ) , i am able to login to NODE 2 and curl the PODIP of NODE1 .
I would like to understand , how communication between container in NODE 1 and NODE 2 even though am not using port 80 of the node.
Appreciate some insights on the same.
You should start by reading an overview on Networking in Kubernetes. The question you are asking is about the overlay network. The exact workings of the overlay network is viewed as an implementation detail and there are many different networking solutions (GKE is running on GCE). GKE is using kubenet.
You might find the talk Illustrated Guide To Kubernetes Networking useful.