Kubernetes ReplicaSets with YAML

Step-01: Create ReplicaSet Definition¶

01-replicaset-definition.yml

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myapp2-rs
spec:
  replicas: 3 # 3 Pods should exist at all times.
  selector:  # Pods label should be defined in ReplicaSet label selector
    matchLabels:
      app: myapp2
  template:
    metadata:
      name: myapp2-pod
      labels:
        app: myapp2 # Atleast 1 Pod label should match with ReplicaSet Label Selector
    spec:
      containers:
      - name: myapp2
        image: stacksimplify/kubenginx:2.0.0
        ports:
          - containerPort: 80

Step-02: Create ReplicaSet¶

Create ReplicaSet with 3 Replicas

# Create ReplicaSet
kubectl apply -f 01-replicaset-definition.yml

# List Replicasets
kubectl get rs

Delete a pod

ReplicaSet immediately creates the pod.

# List Pods
kubectl get pods

# Delete Pod
kubectl delete pod <Pod-Name>

Step-03: Create LoadBalancer Service for ReplicaSet¶

apiVersion: v1
kind: Service
metadata:
  name: replicaset-loadbalancer-service
spec:
  type: LoadBalancer 
  selector: 
    app: myapp2 
  ports: 
    - name: http
      port: 80
      targetPort: 80

- Create LoadBalancer Service for ReplicaSet & Test

# Create LoadBalancer Service
kubectl apply -f 02-replicaset-LoadBalancer-servie.yml

# List LoadBalancer Service
kubectl get svc

# Access Application
http://<Load-Balancer-Service-IP>

Step-04: Clean-Up Kubernetes ReplicaSet and Service¶

# Change Directory
cd kube-manifests

# Delete Pod
kubectl delete -f 01-replicaset-definition.yml

# Delete Service
kubectl delete -f  02-replicaset-LoadBalancer-servie.yml

API References¶

ReplicaSet