🚀 CI/CD Pipeline for Node.js with Jenkins & Docker (Windows + Linux)

In this deeply detailed tutorial, we'll build a complete CI/CD pipeline using Jenkins to automate the following:

• Create a simple Node.js app
• Write a Dockerfile to containerize the app
• Install and configure Jenkins on Windows and Linux
• Write a Jenkinsfile to automate testing and Docker deployment
• Use Jenkins secrets to store Docker credentials

---

🧱 Step 1: Create Your Node.js Application

1. Create the project directory

mkdir ci-cd-node-app-jenkins
cd ci-cd-node-app-jenkins

2. Initialize Node.js project

npm init -y

This creates a package.json file with default values.

3. Create a simple app

Create index.js:

const sum = require('./sum');

console.log("App started. Sum of 2 and 3 is:", sum(2, 3));

Create sum.js:

function sum(a, b) {
  return a + b;
}

module.exports = sum;

4. Add a test using Jest

Install Jest:

npm install --save-dev jest

Update package.json:

"scripts": {
  "test": "jest"
}

Create sum.test.js:

const sum = require('./sum');

test('adds 2 + 3 to equal 5', () => {
  expect(sum(2, 3)).toBe(5);
});

5. Add .gitignore

node_modules
.env

---

🐳 Step 2: Add Dockerfile

Create Dockerfile:

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
CMD ["node", "index.js"]

To test locally:

docker build -t yourusername/jenkins-node-app .
docker run yourusername/jenkins-node-app

---

🔧 Step 3: Install Jenkins

🔷 On Windows:

1. Download Jenkins from jenkins.io
2. Run the installer
3. Install recommended plugins
4. Create first admin user
5. Setup "Git" and "Node.js" in Global Tool Configuration

📌 Also install Docker Desktop and make sure it works via command line (docker --version)

🐧 On Linux (Ubuntu):

sudo apt update && sudo apt install -y openjdk-17-jdk git docker.io
curl -fsSL https://pkg.jenkins.io/debian/jenkins.io-2023.key | sudo tee \
  /usr/share/keyrings/jenkins-keyring.asc > /dev/null

echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \
  https://pkg.jenkins.io/debian binary/ | sudo tee \
  /etc/apt/sources.list.d/jenkins.list > /dev/null

sudo apt update && sudo apt install jenkins
sudo systemctl start jenkins
sudo systemctl enable jenkins

Then:

sudo usermod -aG docker jenkins
sudo systemctl restart jenkins

---

🔑 Step 4: Add DockerHub Secrets to Jenkins

Navigate to:

• Manage Jenkins → Credentials → Global → Add Credentials

Add two "Secret text":

• ID: docker-username, Value: your Docker username
• ID: docker-password, Value: your Docker password

These will be injected using Jenkins credentials() syntax.

---

📝 Step 5: Create Jenkinsfile

▶ Jenkinsfile for Windows

pipeline {
  agent any

  tools {
    nodejs "nodejs20"
  }

  environment {
    DOCKERHUB_USERNAME = credentials('docker-username')
    DOCKERHUB_PASSWORD = credentials('docker-password')
  }

  stages {
    stage('Checkout Code') {
      steps {
        git 'https://github.com/TejeshKumarGantyada/4-cicd-pipeline-with-jenkins.git'
      }
    }

    stage('Install Dependencies') {
      steps {
        bat 'npm install'
      }
    }

    stage('Run Tests') {
      steps {
        bat 'npm test'
      }
    }

    stage('Docker Build') {
      steps {
        bat "docker build -t %DOCKERHUB_USERNAME%/jenkins-node-app:latest ."
      }
    }

    stage('Docker Login') {
      steps {
        bat "echo %DOCKERHUB_PASSWORD% | docker login -u %DOCKERHUB_USERNAME% --password-stdin"
      }
    }

    stage('Docker Push') {
      steps {
        bat "docker push %DOCKERHUB_USERNAME%/jenkins-node-app:latest"
      }
    }
  }
}

▶ Jenkinsfile for Linux

pipeline {
  agent any

  tools {
    nodejs "nodejs20"
  }

  environment {
    DOCKERHUB_USERNAME = credentials('docker-username')
    DOCKERHUB_PASSWORD = credentials('docker-password')
  }

  stages {
    stage('Checkout Code') {
      steps {
        git 'https://github.com/TejeshKumarGantyada/4-cicd-pipeline-with-jenkins.git'
      }
    }

    stage('Install Dependencies') {
      steps {
        sh 'npm install'
      }
    }

    stage('Run Tests') {
      steps {
        sh 'npm test'
      }
    }

    stage('Docker Build') {
      steps {
        sh "docker build -t $DOCKERHUB_USERNAME/jenkins-node-app:latest ."
      }
    }

    stage('Docker Login') {
      steps {
        sh "echo $DOCKERHUB_PASSWORD | docker login -u $DOCKERHUB_USERNAME --password-stdin"
      }
    }

    stage('Docker Push') {
      steps {
        sh "docker push $DOCKERHUB_USERNAME/jenkins-node-app:latest"
      }
    }
  }
}

---

✅ Step 6: Run the Pipeline

1. In Jenkins, create a New Item → Pipeline

2. Under Pipeline → Definition, select Pipeline from SCM

3. Set:

   • SCM: Git
   • Repository URL: https://github.com/TejeshKumarGantyada/4-cicd-pipeline-with-jenkins.git
   • Script Path: Jenkinsfile

4. Click Save, then Build Now

---

🧪 Validate the Image

Go to Docker Hub → Your Repo → Check for jenkins-node-app:latest Run locally if needed:

docker pull yourusername/jenkins-node-app