🐳 Two-Tier Flask + MySQL App with Docker Networking

This project demonstrates how to set up a two-tier application using Docker containers:

• A Flask-based frontend running a simple web app
• A MySQL database backend
  Connected via a user-defined Docker bridge network to enable inter-container communication.

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🚀 What This Project Covers

• Launching an EC2 instance and SSH connection using a .pem file
• Installing Docker on Ubuntu (WSL or EC2)
• Cloning this repository
• Building a custom Docker image for the Flask app
• Creating a user-defined Docker network
• Running MySQL and Flask app containers on the same network
• Testing the application via browser and MySQL shell

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🔧 Prerequisites

• AWS EC2 instance (Ubuntu preferred)
• Docker installed
• Git installed
• SSH access with PEM file

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🐳 Docker Commands Used

Build Flask App Image

docker build -t two-tier-app .

Create Custom Network

docker network create two-tier -d bridge

Run MySQL Container

docker run -d --name mysql --network two-tier \
  -e MYSQL_ROOT_PASSWORD=root \
  -e MYSQL_DATABASE=devops \
  mysql

Run Flask App Container

docker run -d -p 5000:5000 --network two-tier \
  -e MYSQL_HOST=mysql \
  -e MYSQL_USER=root \
  -e MYSQL_PASSWORD=root \
  -e MYSQL_DB=devops \
  two-tier-app:latest

🌐 Access the App

Once both containers are running, open your browser and go to:

http://<your-ec2-public-ip>:5000

Make sure port 5000 is open in your EC2 security group.

🧪 Check MySQL Database

docker exec -it <mysql_container_id> bash
mysql -u root -p

SHOW DATABASES;
USE devops;
SELECT * FROM messages;

Watch Tutorial on YouTube

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