Kubernetes: How to allow two pods running in same/different namespace communicate irrespective of the protocol using a servicename?

By default, pods can communicate with each other by their IP address, regardless of the namespace they're in.

You can see the IP address of each pod with:

kubectl get pods -o wide --all-namespaces

However, the normal way to communicate within a cluster is through Service resources.

A Service also has an IP address and additionally a DNS name. A Service is backed by a set of pods. The Service forwards requests to itself to one of the backing pods.

The fully qualified DNS name of a Service is:

<service-name>.<service-namespace>.svc.cluster.local

This can be resolved to the IP address of the Service from anywhere in the cluster (regardless of namespace).

For example, if you have:

• Namespace ns-a: Service svc-a → set of pods A
• Namespace ns-b: Service svc-b → set of pods B

Then a pod of set A can reach a pod of set B by making a request to:

svc-b.ns-b.svc.cluster.local

You can put the Pods behind Services and use Service DNS for communication. Calls to service-name allow Pods in the same namespace to communicate. Calls to service-name.namespace allow Pods in different namespaces to communicate.