DevOps Classroom notes 09/Oct/2026

Kubernetes ReplicationController (RC) and ReplicaSet (RS)

To deploy RelipcationController create file rc.yaml and add below yaml data

apiVersion: v1
kind: ReplicationController
metadata:
  name: nopcommerce-rc
  labels:
    app: nopcommerce
spec:
  replicas: 3
  selector:
    app: nopcommerce
  template:
    metadata:
      labels:
        app: nopcommerce
    spec:
      containers:
      - name: nopcommerce-container
        image: httpd:latest
        ports:
        - containerPort: 80
        resources:
          limits:
            memory: "512Mi"
            cpu: "500m"
          requests:
            memory: "256Mi"
            cpu: "250m"

# deploy yaml file
kubectl apply -f rc.yaml

# get all pods 
kubectl get pods  # verify pods == replicas count
kuebctl get po

# try to delete pod and verify again it will create new pod
kubectl delete pods <podnames>

# Verify rc 
kubectl get replicationcontroller 
kubectl get rc

To deploy Relipcaset create file rs.yaml and add below yaml data

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: httpd-rs
  labels:
    app: apache2
    environment: production
spec:
  replicas: 2
  selector:
    matchLabels:
      app: apache2
      environment: production
  template:
    metadata:
      labels:
        app: apache2
        environment: production
    spec:
      containers:
        - name: apache2
          env:
            - name: ENVIRONMENT
              value: production
            - name: APP_VERSION
              value: "4.0"
          image: httpd:latest
          ports:
            - name: http
              protocol: TCP
              containerPort: 80
            

# deploy yaml file
kubectl apply -f rs.yaml

# get all pods 
kubectl get pods  # verify pods == replicas count
kuebctl get po

# try to delete pod and verify again it will create new pod
kubectl delete pods <podnames>

# Verify rc 
kubectl get replicaset
kubectl get rs

Deployment

• A deployement manage Replicaset. which it trun to provide
  • Desire state for pods
  • Rolling update and rollback
  • revision History versions

Rfere_here for sample deployment yaml

kubectl apply -f deployment.yaml 

kubectl get rs # see rs name is deployment name + uniqe id 

kubectl get pod # sea pods name will deployment name + rs uniqe id + every pod will its own id 

kubectl scale deployment <deployment-name> --replicas=0

kubectl scale deployment nginx-deployment --replicas=0 # scale down

kubectl scale deployment nginx-deployment --replicas=5 # scale up 

Kubectl delete deployment <deployment name >

kubect get deployement # full cmd

kubectl get deploy # short cmd

Offical docs