Introduction

In this project, I automated the deployment of a Flask and MySQL two-tier application on an AWS EC2 Ubuntu instance using Shell Scripting and Docker.

The automation script performs the following tasks:

• Clones the application source code from GitHub

• Installs Docker and Git

• Configures Docker services

• Creates a Docker network

• Deploys a MySQL container

• Builds and deploys the Flask application container

• Verifies the deployment

---

Project Architecture

GitHub Repository
        │
        ▼
   AWS EC2 Instance
        │
        ▼
   Shell Script
        │
 ┌──────┴──────┐
 ▼             ▼
MySQL      Flask App
Container  Container
        │
        ▼
 Application Access

---

Complete Shell Script

#!/bin/bash

# Deploy Flask + MySQL Two-Tier Application

code_clone() {
    echo "Cloning the Flask application..."

    if [ -d "two-tier-flask-app" ]; then
        echo "Code directory already exists."
        cd two-tier-flask-app || exit 1
    else
        git clone https://github.com//user name two-tier-flask-app.git || {
            echo "Failed to clone repository."
            return 1
        }

        cd two-tier-flask-app || exit 1
    fi
}

install_requirements() {
    echo "Installing Docker and Git..."

    sudo apt-get update

    sudo apt-get install -y docker.io git || {
        echo "Failed to install dependencies."
        return 1
    }
}

required_restarts() {
    echo "Starting Docker service..."

    sudo systemctl start docker
    sudo systemctl enable docker

    sudo chown $USER /var/run/docker.sock || {
        echo "Failed to configure Docker permissions."
        return 1
    }
}

deploy_mysql() {
    echo "Creating Docker network..."

    docker network create twotier 2>/dev/null || true

    echo "Starting MySQL container..."

    docker rm -f mysql 2>/dev/null || true

    docker run -d \
        --name mysql \
        -v mysql-data:/var/lib/mysql \
        --network twotier \
        -e MYSQL_DATABASE=mydb \
        -e MYSQL_ROOT_PASSWORD=admin \
        -p 3306:3306 \
        mysql:5.7 || {
            echo "Failed to start MySQL container."
            return 1
        }

    echo "Waiting for MySQL to initialize..."
    sleep 30
}

deploy_flask() {
    echo "Building Flask image..."

    docker build -t flaskapp . || {
        echo "Docker build failed."
        return 1
    }

    docker rm -f flaskapp 2>/dev/null || true

    echo "Starting Flask container..."

    docker run -d \
        --name flaskapp \
        --network twotier \
        -e MYSQL_HOST=mysql \
        -e MYSQL_USER=root \
        -e MYSQL_PASSWORD=admin \
        -e MYSQL_DB=mydb \
        -p 5000:5000 \
        flaskapp:latest || {
            echo "Failed to start Flask container."
            return 1
        }
}

verify_deployment() {
    echo "Running containers:"
    docker ps
}

echo "********** FLASK APPLICATION DEPLOYMENT STARTED **********"

code_clone || exit 1
install_requirements || exit 1
required_restarts || exit 1
deploy_mysql || exit 1
deploy_flask || exit 1
verify_deployment

echo "********** DEPLOYMENT COMPLETED SUCCESSFULLY **********"

---

Step 1: Clone the Application Repository

The code_clone() function checks whether the project directory already exists. If not, it clones the repository from GitHub.

git clone https://github.com/username/two-tier-flask-app.git

This helps avoid duplicate cloning and ensures the application source code is available on the EC2 instance.

---

Step 2: Install Required Packages

The install_requirements() function updates the package list and installs Docker and Git.

sudo apt-get update
sudo apt-get install -y docker.io git

Docker is required for containerization, and Git is used to clone the source code.

---

Step 3: Configure Docker Service

The required_restarts() function starts and enables Docker services.

sudo systemctl start docker
sudo systemctl enable docker
sudo chown $USER /var/run/docker.sock

This ensures Docker starts automatically after a reboot and can be accessed without permission issues.

---

Step 4: Create Docker Network

Before deploying containers, a dedicated Docker network named twotier is created.

docker network create twotier

This network allows communication between the Flask and MySQL containers.

---

Step 5: Deploy MySQL Container

The deploy_mysql() function creates and runs a MySQL container.

docker run -d \
--name mysql \
-v mysql-data:/var/lib/mysql \
--network twotier \
-e MYSQL_DATABASE=mydb \
-e MYSQL_ROOT_PASSWORD=admin \
-p 3306:3306 \
mysql:5.7

Configuration

Parameter	Value
Database	mydb
Username	root
Password	admin
Port	3306

The Docker volume ensures that database data persists even if the container is recreated.

---

Step 6: Build Flask Docker Image

The Flask application image is built using the Dockerfile available in the repository.

docker build -t flaskapp .

This creates a reusable Docker image named flaskapp.

---

Step 7: Deploy Flask Container

The Flask container is launched and connected to the MySQL container through the Docker network.

docker run -d \
--name flaskapp \
--network twotier \
-e MYSQL_HOST=mysql \
-e MYSQL_USER=root \
-e MYSQL_PASSWORD=admin \
-e MYSQL_DB=mydb \
-p 5000:5000 \
flaskapp:latest

The Flask application uses these environment variables to connect to the MySQL database.

---

Step 8: Verify Deployment

The deployment status is checked using:

docker ps

Expected output:

CONTAINER ID   IMAGE         NAME
xxxxxxxxxx     mysql:5.7     mysql
xxxxxxxxxx     flaskapp      flaskapp

---

Access the Application

Open your browser and navigate to:

http://<EC2-PUBLIC-IP>:5000

Make sure the EC2 Security Group allows:

• Port 22 (SSH)

• Port 5000 (Flask Application)

---

Conclusion

This project demonstrates how Shell Scripting can automate the deployment of a Dockerized Flask and MySQL two-tier application on AWS EC2. The automation reduces manual effort, improves consistency, and follows modern DevOps deployment practices.

By integrating GitHub, Docker, AWS EC2, and Bash scripting, we can achieve a reliable and repeatable deployment process suitable for real-world applications.

This version is ready to paste into Hashnode with both the explanation and the actual script embedded in the article.