Liveness probe concept in Kubernetes - Mini Project: Build & Apply

Liveness Probe Concept in Kubernetes

📖 Scenario: You are managing a web application running inside a Kubernetes cluster. To keep the application healthy, you want Kubernetes to check if the app is alive and restart it if it stops responding.

🎯 Goal: Learn how to add a livenessProbe to a Kubernetes pod configuration to automatically detect and recover from application failures.

📋 What You'll Learn

Create a basic pod YAML manifest with a container running nginx

Add a liveness probe configuration using an HTTP GET request

Set probe parameters like initial delay and period

Verify the pod manifest includes the liveness probe correctly

💡 Why This Matters

🌍 Real World

Liveness probes help keep applications running smoothly by letting Kubernetes detect and fix problems automatically.

💼 Career

Understanding liveness probes is essential for Kubernetes administrators and DevOps engineers to maintain healthy containerized applications.

1

Create a basic pod manifest

Create a Kubernetes pod manifest YAML named pod.yaml with a pod named webapp running the nginx:latest container image.

Kubernetes

# Create a pod manifest with name 'webapp' and container image 'nginx:latest'
# Your code here

Need a hint?

Use apiVersion: v1, kind: Pod, and specify metadata.name and spec.containers with the nginx image.

2

Add liveness probe configuration

Add a livenessProbe section under the container in pod.yaml. Use an httpGet probe that checks path / on port 80.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: webapp
spec:
  containers:
  - name: nginx
    image: nginx:latest
    # Add livenessProbe with httpGet path '/' port 80
    # Your code here

Need a hint?

Indent livenessProbe under the container and specify httpGet with path and port.

3

Set probe timing parameters

Add initialDelaySeconds: 5 and periodSeconds: 10 under the livenessProbe in pod.yaml to control when and how often the probe runs.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: webapp
spec:
  containers:
  - name: nginx
    image: nginx:latest
    livenessProbe:
      httpGet:
        path: /
        port: 80
      # Add initialDelaySeconds: 5 and periodSeconds: 10
      # Your code here

Need a hint?

Place initialDelaySeconds and periodSeconds at the same level as httpGet inside livenessProbe.

4

Display the final pod manifest

Print the complete contents of pod.yaml to verify the liveness probe is configured correctly.

Kubernetes

# Print the pod manifest content
# Your code here

Need a hint?

Use multiple print statements to output each line of the YAML manifest exactly as shown.