CI/CD Pipeline Setup

Objective

Deploy Express (Node.js) and Flask (Python) applications on AWS EC2 using Jenkins, Docker, GitHub Webhooks, and PM2.

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Documentation

• Documentation
• Github URL

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Tools Used

Tool	Purpose
AWS EC2	Ubuntu server to host all services
Jenkins	CI/CD automation server
Docker	Containerization of frontend & backend apps
GitHub	Source code repository with webhook integration
PM2	Process manager to keep apps running after instance restart

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Part 1 — EC2 Setup & Direct Deployment

Steps Followed

# 1. Create an EC2 instance with Ubuntu AMI and SSH into it

# 2. Update the system
sudo apt update && sudo apt upgrade -y

# 3. Verify pre-installed tools
python3 --version
git -v

# 4. Install Node.js
sudo apt install nodejs -y

# 5. Clone the repository
git clone https://github.com/ChetanaMali/fullstack-docker-project

# 6. Install Backend dependencies (Flask)
cd Backend
pip install -r requirements.txt

# 7. Install Frontend dependencies (Express)
cd Frontend
npm install

# 8. Run apps manually to test
cd Frontend && npm start        # Express on port 3000
cd Backend && python app.py     # Flask on port 5000

# 9. Install PM2 globally
sudo npm install -g pm2

# 10. Start apps with PM2
cd Frontend && pm2 start server.js
cd Backend && pm2 start app.py
pm2 list

Security Group Configuration

Port	Protocol	Purpose
22	SSH	Remote access
8080	TCP	Jenkins
3000	TCP	Express (Node.js)
5000	TCP	Flask (Python)
9000	TCP	Express via Docker
8000	TCP	Flask via Docker

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Express Deployment on EC2 (Port 3000)

• Deployed Express (Node.js) application directly on EC2 on port 3000
• Used PM2 as a process manager so the app keeps running even after the instance restarts

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Flask Deployment on EC2 (Port 5000)

• Deployed Flask (Python) application directly on EC2 on port 5000
• Used PM2 to keep the Flask app running persistently after instance restart

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Part 2 — Jenkins + Docker CI/CD Pipeline

Jenkins Installation

• Created a GitHub Gist with all steps and commands to install Jenkins
• https://gist.github.com/ChetanaMali/849f4a01ee49d42fdc879593e0f475bb

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Docker Installation

• Created a GitHub Gist with all steps and commands to install Docker
• https://gist.github.com/ChetanaMali/16a7f4199814298fff132a3403563f93

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Add Jenkins User to Docker Group

sudo usermod -aG docker jenkins
sudo systemctl restart jenkins

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GitHub Webhook Integration

• Configured GitHub webhook to automatically trigger Jenkins pipeline on every git push
• Jenkins job → Build Triggers → ✅ GitHub hook trigger for GITScm polling

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Flask Pipeline — Freestyle

• Created a Freestyle pipeline in Jenkins for the Flask application
• Connected GitHub repository and enabled webhook trigger to automate deployment

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Express Pipeline — Jenkinsfile

• Created a Pipeline job in Jenkins for the Express application
• Created a Jenkinsfile inside the project repository
• Provided the Jenkinsfile location in the Jenkins pipeline configuration

pipeline {
    agent any
    stages {
        stage('Stop & Remove Old Container') {
            steps {
                sh '''
                    docker stop frontend || true
                    docker rm frontend || true
                '''
            }
        }
        stage('Build Image') {
            steps {
                sh 'cd $WORKSPACE/Frontend && docker build -t frontend .'
            }
        }
        stage('Run Container') {
            steps {
                sh 'docker run -d -p 9000:3000 --name frontend frontend'
            }
        }
    }
}

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Express Deployment using Docker (Port 9000)

• Containerized the Express app using Docker
• Deployed on port 9000 to verify Docker-based deployment works independently
• Used Jenkins pipeline to fully automate the build and deployment process

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Flask Deployment using Docker (Port 8000)

• Containerized the Flask app using Docker
• Deployed on port 8000 to verify Docker-based deployment works independently
• Used Jenkins pipeline to fully automate the build and deployment process

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Pipeline Flow

Git Push → GitHub Webhook → Jenkins Triggers
                ↓
          Pull Latest Code
                ↓
    Stop & Remove Old Container
                ↓
        Build Docker Image
                ↓
        Run New Container
                ↓
          App Live on EC2

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Issues Faced & Resolved

Issue	Solution
Docker permission denied in pipeline	Added jenkins user to docker group
Dockerfile not found in pipeline	Used cd $WORKSPACE/Frontend in shell script

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Result

Successfully deployed both Express and Flask applications on AWS EC2 using two approaches:

• ✅ Direct deployment with PM2 for process persistence
• ✅ Docker-based deployment with Jenkins CI/CD pipeline triggered automatically via GitHub webhooks