zkt25/z2

PI Visualization Web Application on Kubernetes

Overview

This project deploys a Python web application using Flask on a Kubernetes cluster. The application displays the first 300 digits of PI with an interactive visualization. The deployment includes a Namespace, Deployment, StatefulSet (with PersistentVolume and PersistentVolumeClaim), and Service.

Application Description

• The web application visualizes PI digits at the root URL (/).
• Each digit appears one at a time (every 0.5 seconds by default) with a unique color.
• Users can control the animation (start, pause, reset) and adjust the speed.
• The application uses one container image built from the Dockerfile provided.

Containers

• simple-web-app: Runs the Python Flask application on port 5000.

Kubernetes Objects

• Namespace: Isolates all the resources under my-app.
• Deployment: Manages the stateless web application pods with 2 replicas for high availability.
• StatefulSet: Manages stateful application pods that require persistent storage.
• PersistentVolume (PV): Provides persistent storage from the host (1GB).
• PersistentVolumeClaim (PVC): Claims the PV for storage.
• Service: Exposes the web application externally via NodePort 30007.

Networking and Storage

• The application uses Kubernetes networking to enable communication between pods.
• The StatefulSet uses a volume claim template that binds to a PersistentVolume mounted at /data.

Container Configuration

• The container is based on Python and includes Flask.
• It exposes port 5000 to serve the web application.
• Resource limits and readiness probes are configured for better stability.

How to Prepare, Run, Pause, and Delete the Application

1. Prepare the application:

   ./prepare-app.sh
   

   This script builds the Docker image and creates the directory for persistent volume.

2. Start the application:

   ./start-app.sh
   

   This script creates all necessary Kubernetes objects in the correct order.

3. Pause or delete the application:

   ./stop-app.sh
   

   This script removes all Kubernetes objects created by start-app.sh.

Accessing the Application

To access the application:

1. Find the IP address of your Kubernetes node:

   kubectl get nodes -o wide
   

2. Access the application in your browser at:

   http://<NODE_IP>:30007
   

   Where <NODE_IP> is the IP address of any of your Kubernetes nodes.

Troubleshooting

If you encounter issues:

1. Check pod status:

   kubectl get pods -n my-app
   

2. View pod logs:

   kubectl logs <pod-name> -n my-app
   

3. Check service status:

   kubectl get svc -n my-app