Pod lifecycle states in Kubernetes - Mini Project: Build & Apply

Pod lifecycle states

📖 Scenario: You are managing a Kubernetes cluster and want to understand the lifecycle states of a Pod. Pods are the smallest deployable units in Kubernetes that run your containers. Knowing the Pod states helps you monitor and troubleshoot your applications effectively.

🎯 Goal: Learn how to create a Pod manifest, add a label selector, check the Pod's lifecycle state, and display the Pod status using kubectl.

📋 What You'll Learn

Create a Pod manifest YAML file named mypod.yaml with specific metadata and container details

Add a label app: demo to the Pod manifest

Use kubectl get pod with label selector to check the Pod's lifecycle state

Print the Pod's status phase to see its current lifecycle state

💡 Why This Matters

🌍 Real World

Kubernetes Pods run your application containers. Knowing their lifecycle states helps you monitor if your app is running, starting, or has errors.

💼 Career

DevOps engineers and site reliability engineers use Pod lifecycle states daily to ensure applications are healthy and troubleshoot issues quickly.

1

Create the initial Pod manifest

Create a YAML file named mypod.yaml with a Pod manifest that has apiVersion: v1, kind: Pod, metadata name mypod, and a single container named nginx using the image nginx:latest.

Kubernetes

# Create mypod.yaml with apiVersion, kind, metadata name, and container nginx with image nginx:latest
# Your code here

Need a hint?

Remember to include apiVersion, kind, metadata with name, and spec with containers list.

2

Add a label to the Pod manifest

Add a label app: demo under the metadata section in mypod.yaml to help identify the Pod.

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: mypod
  # Add label app: demo below
  # Your code here
spec:
  containers:
  - name: nginx
    image: nginx:latest

Need a hint?

Labels go under metadata as a map with key and value.

3

Check Pod lifecycle state using label selector

Use the command kubectl get pod -l app=demo to list the Pod with label app=demo and observe its lifecycle state in the STATUS column.

Kubernetes

# Run kubectl get pod with label selector app=demo
# Your code here

Need a hint?

The -l flag filters Pods by label.

4

Display the Pod's current lifecycle state

Use the command kubectl get pod mypod -o jsonpath='{.status.phase}' to print the current lifecycle state of the Pod named mypod.

Kubernetes

# Run kubectl get pod mypod with jsonpath to print status.phase
# Your code here

Need a hint?

The -o jsonpath= option extracts specific fields from the Pod JSON output.