<p>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 .</p>

<p>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.</p>

<p>Appreciate some insights on the same.</p>

<p>You should start by reading an overview on <a href="https://kubernetes.io/docs/admin/networking/" rel="nofollow noreferrer">Networking in Kubernetes</a>. The question you are asking is about the <em>overlay network</em>. The exact workings of the overlay network is viewed as an implementation detail and there are many different networking solutions (GKE is running on <a href="https://kubernetes.io/docs/admin/networking/#google-compute-engine-gce" rel="nofollow noreferrer">GCE</a>). GKE is using <a href="https://kubernetes.io/docs/concepts/cluster-administration/network-plugins/#kubenet" rel="nofollow noreferrer"><code>kubenet</code></a>.</p>

<p>You might find the talk <a href="https://speakerdeck.com/thockin/illustrated-guide-to-kubernetes-networking" rel="nofollow noreferrer"><em>Illustrated Guide To Kubernetes Networking</em></a> useful.</p>
