lab12.md

Lab 12: Kubernetes ConfigMaps

Overview

In this lab, you'll delve into Kubernetes ConfigMaps, focusing on managing non-confidential data and upgrading your application for persistence. ConfigMaps provide a way to decouple configuration artifacts from image content, allowing you to manage configuration data separately from the application.

Task 1: Upgrade Application for Persistence

6 Points:

In this task, you'll enhance your application to persist data and explore ConfigMaps in Kubernetes.

1. Upgrade Your Application:
   • Modify your application to:
     • Implement a counter logic in your application to keep track of the number of times it's accessed.
     • Save the counter number in the visits file.
     • Introduce a new endpoint /visits to display the recorded visits.
   • Test the changes:
     • Update your docker-compose.yml to include a new volume with your visits file.
     • Verify that the enhancements work as expected, you must see the updated number in the visits file on the host machine.
     • Update the README.md for your application.

Task 2: ConfigMap Implementation

4 Points:

1. Understand ConfigMaps:

   • Read about ConfigMaps in Kubernetes:
     • ConfigMaps

2. Mount a Config File:

   • Create a files folder with a config.json file.
   • Populate config.json with data in JSON format.
   • Use Helm to mount config.json:
     • Create a configMap manifest, extracting data from config.json using .Files.Get.
     • Update deployment.yaml with Volumes and VolumeMounts.
       • Example
     • Install the updated Helm chart and verify success:
       • Retrieve the list of pods: kubectl get po.
       • Use the pod name as proof of successful deployment.
       • Check the ConfigMap inside the pod, e.g., kubectl exec demo-758cc4d7c4-cxnrn -- cat /config.json.

3. Documentation:

   • Create 12.md in the k8s folder and include the output of relevant commands.

List of Requirements:

• config.json in the files folder.
• configMap retrieving data from config.json using .Files.Get.
• Volumes and VolumeMounts in deployments.yml.
• 12.md documenting the results of commands.

Bonus Task: ConfigMap via Environment Variables

2.5 Points:

1. Upgrade Bonus App:

   • Implement persistence logic in your bonus app.

2. ConfigMap via Environment Variables:

   • Utilize ConfigMap via environment variables in a running container using the envFrom property.
   • Provide proof with the output of the env command inside your container.

Guidelines

• Maintain clear and organized documentation.
• Use appropriate naming conventions for files and folders.
• For your repository PR, ensure it's from the lab12 branch to the main branch.

Note: Clear documentation is crucial to demonstrate successful data persistence and ConfigMap utilization in Kubernetes. Explore the bonus tasks to further enhance your skills.