Working with kubernetes Replication Controller

DevOps

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I want to create 1000s of SIMILAR PODS?

ReplicationController – ReplicasSets – Deployment
Statefulsets – Deamonsets

ReplicationController

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.

Replication
– ONE PODs would replicate(SCALE) to X number of PODS
Controller
– This controller would control #of ACTUAL PODS === #of Desire PODS
– If mis-matched – report back to API Server

apiVersion: v1
kind: ReplicationController
metadata:
  # Unique key of the ReplicationController instance
  name: replicationcontroller-example
spec:
  # 3 Pods should exist at all times.
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      # Run the nginx image
      - name: nginx
        image: scmgalaxy/nginx-devopsschoolv1Code language: PHP (php)
replicationcontroller/replicationcontroller-example created
[root@rajesh rajesh]# kubectl get rc
NAME                            DESIRED   CURRENT   READY   AGE
replicationcontroller-example   3         3         0       3s
[root@rajesh rajesh]# kubectl get rc
NAME                            DESIRED   CURRENT   READY   AGE
replicationcontroller-example   3         3         3       13s
[root@rajesh rajesh]# kubectl get pods
NAME                                  READY   STATUS    RESTARTS   AGE
replicationcontroller-example-8glnd   1/1     Running   0          21s
replicationcontroller-example-b86xm   1/1     Running   0          21s
replicationcontroller-example-fk4fg   1/1     Running   0          21s


[root@rajesh rajesh]# kubectl get pods
NAME                                  READY   STATUS    RESTARTS   AGE
replicationcontroller-example-26fmw   1/1     Running   0          2m5s
replicationcontroller-example-8glnd   1/1     Running   0          5m54s
replicationcontroller-example-df5zh   1/1     Running   0          2m5s
replicationcontroller-example-fk4fg   1/1     Running   0          5m54s
replicationcontroller-example-ps4nk   1/1     Running   0          2m5s
[root@rajesh rajesh]# kubectl delete pod replicationcontroller-example-26fmw replicationcontroller-example-8glnd replicationcontroller-example-df5zh replicationcontroller-example-fk4fg
pod "replicationcontroller-example-26fmw" deleted
pod "replicationcontroller-example-8glnd" deleted
pod "replicationcontroller-example-df5zh" deleted
pod "replicationcontroller-example-fk4fg" deleted
[root@rajesh rajesh]# kubectl get pods
NAME                                  READY   STATUS              RESTARTS   AGE
replicationcontroller-example-5bqxv   0/1     ContainerCreating   0          11s
replicationcontroller-example-dptd7   0/1     ContainerCreating   0          11s
replicationcontroller-example-j5xx9   1/1     Running             0          11s
replicationcontroller-example-prv9r   1/1     Running             0          11s
replicationcontroller-example-ps4nk   1/1     Running             0          3m11s


  254  kubectl -h
  255  clear
  256  kubectl create -h
  257  clear
  258  kubectl create -h
  259  clear
  260  vi rc.yaml
  261  kubectl get rc
  262  kubectl create -f rc.yaml
  263  kubectl get rc
  264  kubectl get pods
  265  kubectl edit rc replicationcontroller-example
  266  kubectl get pods
  267  clear
  268  kubectl get pods
  269  clear
  270  kubectl edit rc replicationcontroller-example
  271  kubectl get pods
  272  clear
  273  kubectl get pods
  274  vi rc.yaml
  275  kubectl apply -f rc.yaml
  276  kubectl get pods
  277  kubectl scale -h
  278  clear
  279   kubectl scale --replicas=10 -f rc.yaml
  280  kubectl get pods
  281   kubectl scale --replicas=5 rs/replicationcontroller-example
  282   kubectl scale --replicas=5 rc/replicationcontroller-example
  283  kubectl get pod
  284  clear
  285  kubectl get pods
  286  kubectl delete pod replicationcontroller-example-26fmw replicationcontroller-example-8glnd replicationcontroller-example-df5zh replicationcontroller-example-fk4fg
  287  kubectl get podsCode language: PHP (php)