Rolling update strategy in Kubernetes - Mini Project: Build & Apply

Kubernetes Rolling Update Strategy

📖 Scenario: You manage a web application running on Kubernetes. You want to update the app to a new version without downtime. Kubernetes rolling update helps replace old app versions with new ones gradually.

🎯 Goal: Learn how to create a Deployment with an initial app version, configure the rolling update strategy, update the app version, and observe the rolling update in action.

📋 What You'll Learn

Create a Deployment YAML with app version 1

Add rolling update strategy with maxSurge and maxUnavailable

Update the Deployment to app version 2

Check the rollout status to confirm update success

💡 Why This Matters

🌍 Real World

Rolling updates let you update live applications without downtime by replacing pods gradually.

💼 Career

DevOps engineers use rolling update strategies daily to deploy new app versions safely in Kubernetes clusters.

1

Create initial Deployment YAML with app version 1

Create a file named deployment.yaml with a Kubernetes Deployment for an app called myapp. Use image nginx:1.19. Set replicas to 3. Include labels app: myapp under metadata and spec.template.metadata. Use container name nginx.

Kubernetes

# Create deployment.yaml with Deployment for myapp using nginx:1.19 and 3 replicas
# Your code here

Need a hint?

Use apiVersion: apps/v1 and set replicas: 3. Labels must be under both metadata and spec.template.metadata.

2

Add rolling update strategy to Deployment

Edit deployment.yaml to add a strategy section under spec. Use type: RollingUpdate. Set rollingUpdate.maxSurge to 1 and rollingUpdate.maxUnavailable to 1.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    app: myapp
spec:
  replicas: 3
  # Add rolling update strategy below
  # Your code here
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80

Need a hint?

Place strategy under spec. Use type: RollingUpdate and set maxSurge and maxUnavailable to 1.

3

Update Deployment to use nginx version 1.21

Change the container image in deployment.yaml from nginx:1.19 to nginx:1.21 to prepare for rolling update.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    app: myapp
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: nginx
        # Change image version to 1.21 below
        # Your code here
        ports:
        - containerPort: 80

Need a hint?

Update the image field under containers to nginx:1.21.

4

Apply Deployment and check rollout status

Run the command kubectl apply -f deployment.yaml to update the Deployment. Then run kubectl rollout status deployment/myapp-deployment to check the rolling update status. Write the exact output you see from the rollout status command.

Kubernetes

# Run kubectl apply and rollout status commands
# Your code here

Need a hint?

After applying, the rollout status command shows deployment "myapp-deployment" successfully rolled out when update finishes.