In this lab we will practice creating replicaset with yaml file

In case you prefer a video, check below our YouTube video for this lab

Task: Create Kubernetes cluster with 3 worker nodes.

Master: 1 node

Worker: 2 node

Solution

Create docker hub account. Docker Hub if you already have one skip this step

Open Play with Kubernetes login with your docker hub account.

Click on start

It will start a 4 hr session

create three instance

click on + ADD NEW INSTANCE three time to add three instances

on first instance enter below command, this node will be master node

kubeadm init --apiserver-advertise-address $(hostname -i) --pod-network-cidr 10.5.0.0/16

enter below command on first node

kubectl apply -f https://raw.githubusercontent.com/cloudnativelabs/kube-router/master/daemonset/kubeadm-kuberouter.yaml

capture output of kubeadm join XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

enter captured command in second and third node

kubeadm join  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Check node status, all 3 nodes should be in ready state

Task: Create a Replicaset with below settings

name: demo
image: nginx
replca: 3
labels:
  app: demo
  type: web

verify with below command

kubectl get rs

vi rs.yaml

apiVersion: apps/v1

kind: ReplicaSet

metadata:

  name: demo

  labels:

    app: demo

    type: web

spec:

  replicas: 3

  selector:

    matchLabels:

      type: web

  template:

    metadata:

      labels:

        type: web

    spec:

      containers:

      - name: demo-nginx

        image: nginx

        ports:

        - containerPort: 80

kubectl apply -f rs.yaml

Task: How many pods are created by Replicaset?

kubectl get pods

Task: Which nodes are pods running on?

kubectl get pods -o wide

Task: Find details on Replicaset created in this lab

kubectl describe rs demo

Task: Use kubectl command to get Replicaset details in yaml format.

kubectl get rs demo -o yaml

Task: Use kubectl command to get Replicaset details in json format.

kubectl get rs demo -o json

Task: Scale replicaset to 5 replicas

verify with below command

kubectl get rs

kubectl scale  rs demo --replicas=5

Task: How many pods are managed by Replicaset?

kubectl get pods

Task: Confirm that pod is managed by Replicaset

kubectl describe pods demo-XXXX

Task: Delete Replicaset we created in this lab

kubectl delete rs demo

Task: Delete all open nodes/instances and close session

1. Select the node and click on DELETE
2. Repeat same for any other open nodes
3. click close session

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