Automated CI/CD Pipeline for a 2-Tier Flask Application on AWS

Project Overview

This project demonstrates an end-to-end CI/CD pipeline for a 2-tier web application built with Flask and MySQL, deployed on an AWS EC2 instance using Docker, Docker Compose, and Jenkins.

The primary goal of this project is to learn and practice DevOps concepts by automating the build and deployment process whenever code is pushed to a GitHub repository.

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What I Learned from This Project

• Building a complete CI/CD pipeline using Jenkins
• Containerizing applications using Docker
• Managing multi-container applications with Docker Compose
• Automating deployments on AWS EC2
• Writing Pipeline-as-Code using a Jenkinsfile
• Understanding real-world DevOps workflows

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🏗️ Architecture Overview

High-level architecture of the project:

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🔄 CI/CD Workflow

1. Developer pushes code to the main branch
2. Jenkins pipeline is triggered automatically
3. Jenkins:
   • Clones the GitHub repository
   • Builds the Flask Docker image
   • Deploys the application using Docker Compose
4. Updated application becomes live on AWS EC2

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Tech Stack

• Cloud: AWS EC2 (Ubuntu 22.04)
• CI/CD Tool: Jenkins
• Containerization: Docker, Docker Compose
• Backend Framework: Flask (Python)
• Database: MySQL
• Version Control: Git & GitHub

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Project Structure

. ├── app.py ├── requirements.txt ├── Dockerfile ├── docker-compose.yml ├── Jenkinsfile └── README.md

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🐳 Docker Configuration

Dockerfile

• Uses python:3.9-slim as the base image
• Installs required system and Python dependencies
• Exposes Flask on port 5000
• Starts the application using python app.py

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Docker Compose Configuration

The docker-compose.yml file defines two services:

Services

• flask

  • Builds the application image
  • Exposes port 5000
  • Connects to the MySQL service

• mysql

  • Uses the official MySQL image
  • Persists data using Docker volumes
  • Exposes port 3306

Both services communicate over a shared Docker network.

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⚙️ Jenkins Pipeline

The Jenkins pipeline is defined using a Jenkinsfile (Pipeline-as-Code).

Pipeline Stages

1. Clone Code

   • Pulls the latest code from the GitHub repository

2. Build Docker Image

   • Builds the Flask application Docker image

3. Deploy with Docker Compose

   • Stops existing containers
   • Deploys updated containers in detached mode

This ensures every push to the repository results in an automatic deployment.

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How to Run This Project

Prerequisites

• AWS EC2 instance (Ubuntu 22.04)
• Docker and Docker Compose installed
• Jenkins installed and running
• Required ports opened in the EC2 security group:
  • 22 (SSH)
  • 5000 (Flask)
  • 8080 (Jenkins)

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Deployment Steps

1. Configure Jenkins with Docker permissions
2. Create a Jenkins pipeline using the repository
3. Push code to the main branch
4. Jenkins automatically builds and deploys the application

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Access the Application

• Flask App:
  http://<EC2_PUBLIC_IP>:5000

• Jenkins Dashboard:
  http://<EC2_PUBLIC_IP>:8080

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📈 Future Enhancements

• Add NGINX reverse proxy
• Use AWS RDS instead of containerized MySQL
• Implement GitHub Webhooks
• Add Secrets Management
• Add Monitoring & Logging (Prometheus, Grafana)

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📌 Disclaimer

This project was built for learning and practice purposes.
It is inspired by existing DevOps tutorials but implemented independently to understand real-world CI/CD concepts and workflows.

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🙌 Acknowledgements

Thanks to the DevOps community and open-source contributors for providing learning resources and inspiration.

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