What is ReplicationController?
Achieving HA and FT requires providing redundancy of components and proper load balancing of incoming traffic between the replicas of components. Let's take a look at the first Kubernetes object that allows you to create and maintain multiple replicas of the Pods in your cluster: ReplicationController. Please note that we are discussing ReplicationController mainly for historical reasons as it was the initial way of creating multiple Pod replicas in Kubernetes. We advise you to use ReplicaSet whenever possible, which is basically the next generation of ReplicationController with an extended specification API.
Tip
The Controller objects in Kubernetes have one main goal: to observe the current and the desired cluster state that is exposed by the Kubernetes API server and command changes that attempt to change the current state to the desired one. They serve as continuous feedback loops, doing all they can to bring clusters to the desired state...
