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

Recreate Update Strategy in Kubernetes

📖 Scenario: You are managing a web application running on Kubernetes. You want to update the application pods so that the old pods are completely terminated before new pods start. This is important to avoid conflicts during the update.

🎯 Goal: Create a Kubernetes Deployment manifest that uses the Recreate update strategy, which terminates all old pods before creating new ones.

📋 What You'll Learn

Create a Deployment named webapp in the default namespace

Use the image nginx:1.21 for the pods

Set the update strategy to Recreate

Set the number of replicas to 2

Expose the pods on container port 80

💡 Why This Matters

🌍 Real World

Using the Recreate update strategy is useful when your application cannot run multiple versions simultaneously or when you want to avoid conflicts during updates.

💼 Career

Understanding update strategies in Kubernetes is essential for DevOps engineers to manage application deployments safely and reliably.

1

Create the basic Deployment manifest

Create a Kubernetes Deployment manifest named webapp with 2 replicas using the image nginx:1.21. Set the container port to 80. Do not add the update strategy yet.

Kubernetes

# Write the Deployment manifest YAML here
# Your code here

Need a hint?

Start by defining apiVersion, kind, metadata, and spec. Use replicas: 2 and set the container image to nginx:1.21. Don't add the update strategy yet.

2

Add the Recreate update strategy

Add the strategy field under spec and set its type to Recreate in the Deployment manifest.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp
  namespace: default
spec:
  replicas: 2
  # Add strategy with type Recreate below
  selector:
    matchLabels:
      app: webapp
  template:
    metadata:
      labels:
        app: webapp
    spec:
      containers:
      - name: nginx
        image: nginx:1.21
        ports:
        - containerPort: 80

Need a hint?

Under spec, add strategy: and set type: Recreate to specify the update strategy.

3

Apply the Deployment manifest

Use the kubectl apply -f deployment.yaml command to create the Deployment in the cluster. Assume the manifest is saved as deployment.yaml.

Kubernetes

# Run the command to apply the deployment manifest
# Your code here

Need a hint?

Use kubectl apply -f deployment.yaml to create or update the Deployment from the YAML file.

4

Verify the update strategy

Run the command kubectl get deployment webapp -o jsonpath='{.spec.strategy.type}' to display the update strategy type of the webapp Deployment.

Kubernetes

# Run the command to check the update strategy
# Your code here

Need a hint?

This command extracts the update strategy type from the Deployment's spec. It should print Recreate.