Replication controller

A Replication Controller ensures that a specified number of pod replicas are running at any given time. If a pod fails or is deleted, the Replication Controller will create a new pod to replace it.

Example Replication Controller Definition

apiVersion: v1
kind: ReplicationController
metadata:
  name: my-rc
  labels:
    app: my-app
    type: frontend
spec:
  replicas: 3
  selector:
    app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-container
        image: my-image

In this example, we define a Replication Controller named my-rc that maintains 3 replicas of a pod with the label app: my-app. The pod template specifies the container to run.

Commands

Create a Replication Controller from a definition file:

kubectl create -f my-rc.yaml

Show the list of Replication Controllers:

kubectl get rc

Detailed information about a Replication Controller:

kubectl describe rc my-rc

Delete a Replication Controller:

kubectl delete rc my-rc

Extract the definition to a file:

kubectl get rc my-rc -o yaml > my-rc-new.yaml

Modify the properties of the Replication Controller:

kubectl edit rc my-rc