Steps To Create A Replication Controller Using YAML

In this blog, We will show you the Steps to create a Replication Controller using YAML in Kubernetes Environment.

REQUIREMENTS

2 Node Cluster ( 1 Master VM with 2 Nodes)
Kubernetes Components

INFRASTRUCTURE OVERVIEW

We have already installed and configured the 2 Node cluster in our demo environment.
Please check the URL https://blog.assistanz.com/steps-to-install-kubernetes-cluster-manually-using-centos-7/ for more information

REPLICATION CONTROLLER CREATION

Create a YAML file using the default editor.

Add the below coding and save it.

apiVersion: v1
kind: ReplicationController
metadata:
    name: rep-pod
spec:
    replicas: 4
    selector:
       app: web
       env: test
    template:
       metadata:
          labels:
             app: web
             env: test
       spec:
          containers:
          - name: rep-cont
            image: nginx

Execute the below command to create a replication controller using YAML file.

Syntax: kubectl apply -f <filename with extension>

Example: kubectl apply -f rc.yml

Command executed successfully.

All the PODs will be in creating status.

After few seconds, all the PODs are in running status.

VERIFYING REPLICATION CONTROLLER

Use the below command to view the list of replication controllers.

kubectl get rc

Note: rc is the short-hand of replication controller

Describe command will use to view the detailed information about the replication controller.

Syntax: kubectl describe rc <replication controller name>

Example: kubectl describe rc rep-pod

DELETING THE REPLICATION POD

Currently, there are four POD’s available in our demo replication controller.

Let’s delete a POD and see how kubernetes reacts.

Kubernetes will start creating a new POD automatically. Kubernetes will keep on checking the desired state. When the desired state fails, kubernetes takes own action to restore the state.

After few seconds, the new POD is in running status and replaced the old one.

EXTERNAL LINKS

https://kubernetes.io/docs/concepts/workloads/controllers/replicationcontroller/

VIDEO

Thanks for reading this blog. We hope it was useful for you learn about creating a replication controller using YAML file in the kubernetes environment.