"Two-Tier Web App with Docker: Flask Frontend + MySQL Backend"

📘 Introduction

In this blog, I’ll walk you through how I deployed a two-tier Flask web application with a MySQL database using Docker containers on an AWS EC2 instance. This setup ensures container isolation, environment consistency, and real-time communication between the app and database via Docker networking.

By the end of this guide, your application will be accessible over the internet with just a public IP and a browser!

☁️ 1. Launching AWS EC2 Instance (Ubuntu)

• Go to AWS EC2 Console.

• Launch a new instance with the following:

  • AMI: Ubuntu 20.04 or 22.04 LTS

  • Instance Type: t2.micro (Free Tier)

  • Storage: 8 GB or more

  • Security Group Rules:

    • SSH (Port 22) – for terminal access

    • HTTP (Port 80) – optional

    • Custom TCP (Port 5000) – to access Flask App

• Key pair: Create or use an existing one (e.g., my-key.pem)

✅ Connect to the instance:

ssh -i my-key.pem ubuntu@your-public-ip

🐳 2. Installing Docker and Git on Ubuntu

sudo apt update
sudo apt install -y docker.io 
sudo usermod -aG docker $USER && newgrp docker

1. sudo apt update
Updates the package list to fetch the latest versions available from repositories.

2. sudo apt install -y docker.io
Installs Docker Engine from Ubuntu’s default repository without asking for confirmation.

3. sudo usermod -aG docker $USER && newgrp docker
Adds your user to the Docker group so you can run Docker without sudo.

🔧 3. Cloning the Flask Project

clone https://github.com/ApurvGujjar07/Two-Tier-Flask-App-.git
cd two-tier-flask-app
ls

You’ll see files like app.py, Dockerfile, etc.

📦 4. Build Flask App Docker Image

docker build -t two-tier-backend .

This command packages the app into a Docker image named two-tier-backend.

🌐 5. Create Docker Network

docker network create mynetwork

This allows containers to communicate internally by name (DNS-style linking).

🐬 6. Run MySQL Container

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

✅ MySQL now runs and is ready for connection on the Docker network.

🚀 7. Run Flask App Container

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

Your Flask app is now running and mapped to port 5000 of your EC2 instance.

🔍 8. Verify Everything is Working

Check running containers

🌐 9. Access App in Browser

• Go to AWS Console → Security Groups

• Add inbound rule:

  • Type: Custom TCP

  • Port: 5000

  • Source: Anywhere (0.0.0.0/0)

Then visit:
🌍 http://<your-public-ip>:5000

✅ You should see the live Flask web app now!

Connect to MySQL and verify DB:

docker exec -it mysql mysql -u root -p
# Enter: root

Then run:

SHOW DATABASES;
USE devops;
SHOW TABLES;
SELECT * FROM messages;

🧠 Conclusion

In this blog, I demonstrated how to:

• Launch an EC2 instance

• Install and configure Docker

• Deploy a two-tier Flask + MySQL app

• Connect containers via Docker network

• Expose the app publicly via port 5000

This is a solid DevOps practice project showing real-world containerization, networking, and deployment skills.

👨‍💻 About the Author

Hi, I'm Apurv Gujjar, a passionate and aspiring DevOps Engineer.
"This project marks the beginning of my journey into the world of DevOps, containerization, and cloud-native application deployment."