Automating Docker container deployment with Jenkins 🐳

Overview

This project demonstrates a modernized CI/CD pipeline using Jenkins, Docker, and Node.js.

Stack:

• Runtime: Node.js 20 (Alpine)
• Database: MongoDB 6.0
• Testing: Mocha, Chai, Supertest
• Infrastructure: Docker Compose, Jenkins Pipeline

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Contents

1. Prerequisites
2. Local Development
3. Jenkins Setup
4. Pipeline Configuration
5. Troubleshooting

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Prerequisites

• Docker Desktop (or Engine) installed.
• Node.js (v18+ recommended for local dev, though app runs in Docker).
• Jenkins (can be run locally or via container).

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Local Development

1. Setup

Runs the application stack (App + MongoDB) locally using Docker Compose. A reliable run.sh script is provided.

# Start the environment and seed the database
./run.sh

This will:

• Build the Node.js image.
• Start MongoDB (v6.0) and the Node app.
• Execute the seed script (seeds/seed.js) to populate the database.

Access the app at: http://localhost:3000

2. Manual Commands

If you prefer running commands manually:

# Start services
docker-compose up -d --build

# Run tests
npm test

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Jenkins Setup

1. Installation

Ensure Jenkins is installed and running. If you are on Ubuntu, you can use the provided setup.sh to install Docker if it's not present.

2. Plugins

Install the following plugins via Manage Jenkins > Plugins:

• Docker Pipeline
• Docker
• Pipeline
• Git
• NodeJS (optional if running builds inside Docker agents)

3. Credentials

1. Go to Manage Jenkins > Credentials.
2. Add a new credential of type Username with password.
3. ID: dockerhub (matches the Jenkinsfile).
4. Enter your Docker Hub username and password.

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Pipeline Configuration

The Jenkinsfile defines the pipeline stages:

1. Cloning Git: Pulls code from the repository.
2. Building Docker Image: Builds the image tagged with the Jenkins BUILD_NUMBER.
3. Deploying: Pushes the image to your configured registry (default: naistangz/docker_automation).
4. Cleanup: Removes local artifacts to save space.

Environment Variables

Edit the environment block in Jenkinsfile to match your updates:

environment {
    registry = "your-dockerhub-username/repo-name"
    registryCredential = "dockerhub"
}

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Troubleshooting

Docker Permission Denied

If Jenkins cannot access the Docker socket:

sudo usermod -aG docker jenkins
sudo systemctl restart jenkins

Database Connection Fails

Ensure the container name in docker-compose.yml matches DB_HOST.

• Correct: mongodb://mongo:27017/posts
• Why: Docker Compose uses service names as hostnames.