"How to permanently delete pods inside "default" namespace? As when I delete pods, they are coming back because of "replication controller".
As this is in a Default namespace, I am sure that we can delete it permanently. Any idea how to do it ?
Read about Replication Controllers, then delete the ReplicationController.
It can't "ensure that a specified number of pod replicas are running" when it's dead.
kubectl delete replicationcontroller <name>
I'd like to add some update to what was already said in previous answer. Basically in kubernetes you have several abstraction layers. As you can read in the documentation:
A Pod is the basic execution unit of a Kubernetes application–the smallest and simplest unit in the Kubernetes object model that you create or deploy. A Pod represents processes running on your Cluster .
It is rarely deployed as separate entity. In most cases it is a part of higher level object such as Deployment or ReplicationController. I would advise you to familiarize with general concept of controllers, especially Deployments, as they are currently the recommended way of setting up replication [source]:
Note: A Deployment that configures a ReplicaSet is now the recommended way to set up replication.
As you can read further:
A ReplicationController ensures that a specified number of pod replicas are running at any one time. In other words, a ReplicationController makes sure that a pod or a homogeneous set of pods is always up and available.
It applies also to situation when certain pods are deleted by user. Replication controller doesn't care why the pods were deleted. Its role is just to make sure they are always up and running. Its very simple concept. When you don't want certain pods to exist any more, you must get rid of the higher level object that manages them and ensures they are always available.