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Thu Kha Kyawe
Thu Kha Kyawe

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13.Deploy Highly Available Pods with ReplicationController

#aws #kuberneteslevel1

Lab Information

The Nautilus DevOps team is establishing a ReplicationController to deploy multiple pods for hosting applications that require a highly available infrastructure. Follow the specifications below to create the ReplicationController:

Create a ReplicationController using the httpd image with latest tag, and name it httpd-replicationcontroller.

Assign labels app as httpd_app, and type as front-end. Ensure the container is named httpd-container and set the replica count to 3.
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All pods should be running state post-deployment.

Note: The kubectl utility on jump_host is configured to operate with the Kubernetes cluster.

Lab Solutions

Step 1: Create the ReplicationController YAML file 

cat > httpd-replicationcontroller.yaml <<EOF
apiVersion: v1
kind: ReplicationController
metadata:
  name: httpd-replicationcontroller
spec:
  replicas: 3
  selector:
    app: httpd_app
    type: front-end
  template:
    metadata:
      labels:
        app: httpd_app
        type: front-end
    spec:
      containers:
      - name: httpd-container
        image: httpd:latest
        ports:
        - containerPort: 80
EOF
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Explanation of the configuration:

ReplicationController name: httpd-replicationcontroller

Image: httpd:latest

Labels: app: httpd_app and type: front-end

Container name: httpd-container

Replica count: 3

Step 2: Apply the ReplicationController 

kubectl apply -f httpd-replicationcontroller.yaml
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Step 3: Verify the ReplicationController was created 

kubectl get replicationcontroller httpd-replicationcontroller
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Step 4: Check the pods created by the ReplicationController 

kubectl get pods
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Step 5: Verify pod details and labels 

kubectl describe replicationcontroller httpd-replicationcontroller
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Step 6: Verify all pods are running 

kubectl get pods -l app=httpd_app,type=front-end -o wide
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