zkt25/z1/README.md

Docker Web Application

Overview

This is a Dockerized web application consisting of two services:

• Web Service: A simple Python Flask application serving HTTP endpoints.
• Database Service: A MySQL 8.0 database that stores its data in a persistent volume.

The web service demonstrates basic functionality and includes an endpoint (/dbtest) to test connectivity with the database service.

Deployment Requirements

• Docker: Ensure Docker is installed and running.
• Docker Compose: Version 3.8 or later is required to run the multi-container application.

Application Architecture

• Virtual Network:
  A custom Docker network app-network is used to allow seamless communication between containers.

• Named Volume:
  A persistent volume db_data is defined to store MySQL database data, ensuring data persistence between container restarts.

Container Configurations

• Web Service Container:

  • Image: Custom built from the provided Dockerfile.
  • Port: Exposes port 5000.
  • Environment Variables: Set for database connectivity (e.g., MYSQL_HOST, MYSQL_USER, MYSQL_PASSWORD, MYSQL_DATABASE).
  • Restart Policy: Configured to always restart on failure.

• Database Service Container:

  • Image: Official mysql:8.0 image.
  • Ports: Exposes port 3306.
  • Environment Variables: Defines MYSQL_ROOT_PASSWORD and MYSQL_DATABASE for initial configuration.
  • Volume: Uses named volume db_data for data persistence.
  • Restart Policy: Configured to always restart on failure.

Used Containers

• web: The Flask-based web server.
• db: The MySQL database server.

How to Use the Application

1. Prepare the Application:
   Run the following command to build images and create required networks/volumes:

   ./prepare-app.sh
   
   

2. Start the Application: Launch the containers with:

   ./start-app.sh
   
   You should see a message:
       Running app ...
       The app is available at http://localhost:5000
   
   

3. Interact with the Application:

   • Open your web browser and go to http://localhost:5000 to view the home page. • Visit http://localhost:5000/status for the application status. • Visit http://localhost:5000/dbtest to test the database connectivity.

4. Stop the Application: To stop all running services without removing their state:

   ./stop-app.sh
   
   

5. Remove the Application: When you want to completely remove all containers, networks, and volumes:

   ./remove-app.sh