Immutable ConfigMaps in Kubernetes - Mini Project: Build & Apply

Immutable ConfigMaps

📖 Scenario: You are managing configuration for a web application running on Kubernetes. To prevent accidental changes to configuration data, you want to create an immutable ConfigMap. This means once created, the ConfigMap cannot be changed, ensuring stability and safety.

🎯 Goal: Create an immutable ConfigMap in Kubernetes with specific data, add a label to it, and verify its immutability by printing the ConfigMap details.

📋 What You'll Learn

Create a ConfigMap named app-config with data keys APP_MODE set to production and LOG_LEVEL set to info

Add a label environment: production to the ConfigMap

Set the ConfigMap to be immutable

Print the ConfigMap YAML to verify the configuration

💡 Why This Matters

🌍 Real World

Immutable ConfigMaps are used in production Kubernetes environments to ensure configuration data does not change unexpectedly, which helps maintain application stability.

💼 Career

Understanding how to create and manage immutable ConfigMaps is important for DevOps engineers and Kubernetes administrators to enforce configuration safety and best practices.

1

Create the initial ConfigMap data

Create a ConfigMap YAML named app-config.yaml with apiVersion set to v1, kind set to ConfigMap, and metadata.name set to app-config. Add data with keys APP_MODE set to production and LOG_LEVEL set to info.

Kubernetes

# Create a ConfigMap YAML with name 'app-config' and data keys 'APP_MODE' and 'LOG_LEVEL'
# Your code here

Need a hint?

Use YAML syntax to define the ConfigMap with the required fields and data keys.

2

Add a label to the ConfigMap

Add a labels section under metadata with the label environment: production in the app-config.yaml file.

Kubernetes

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
  # Add labels here
  # Your code here
data:
  APP_MODE: production
  LOG_LEVEL: info

Need a hint?

Indent the labels section properly under metadata.

3

Make the ConfigMap immutable

Add the field immutable: true under the root level of the ConfigMap YAML in app-config.yaml to make the ConfigMap immutable.

Kubernetes

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
  labels:
    environment: production
# Add immutable field below
# Your code here
data:
  APP_MODE: production
  LOG_LEVEL: info

Need a hint?

The immutable field is a sibling to metadata and data.

4

Print the ConfigMap YAML

Run the command kubectl apply -f app-config.yaml to create the ConfigMap, then run kubectl get configmap app-config -o yaml to print the ConfigMap YAML and verify it is immutable.

Kubernetes

# Run kubectl commands to apply and print the ConfigMap
# Your code here

Need a hint?

Use kubectl apply -f app-config.yaml to create the ConfigMap and kubectl get configmap app-config -o yaml to see its details.