Jenkins Configuration (Start to End)

This guide covers the complete Jenkins configuration for CI/CD pipelines with Docker deployments.

Prerequisites (What You Should Have)

Before starting, verify you have:

[x] Jenkins running
[x] Pipeline job created
[x] Builds are successful
[x] Jenkins accessible via domain
[x] Docker already running containers

Your Jenkins dashboard should look like this:

Jenkins Dashboard

Step 1: Global Jenkins Configuration

1.1 Configure Executors (Important for Performance)

Go to:

Manage Jenkins → Nodes → Built-In Node → Configure

Set:

# of executors: 2

Click Save

1.2 Git Configuration

Go to:

Manage Jenkins → Tools

Under Git installations:

Field	Value
Name	Default
Path to Git	/usr/bin/git

Click Save

Step 2: Required Plugins (Verify)

Go to:

Manage Jenkins → Plugins → Installed

Make sure these plugins exist:

[x] Git
[x] Pipeline
[x] Docker Pipeline
[x] GitHub Integration Plugin (recommended)

Tip

If any plugin is missing → Install it → Restart Jenkins.

Step 3: Credentials (For Private Repos)

Go to:

Manage Jenkins → Credentials → System → Global → Add Credentials

Configure:

Field	Value
Kind	Username with password (or GitHub token)
ID	github-creds
Username	Your GitHub username
Password	Your GitHub token

Click Save

Note

If your repository is public, you can skip this step.

Step 4: Jenkinsfile (Most Important)

Create a Jenkinsfile in your project's root directory:

pipeline {
    agent any

    environment {
        APP_NAME = "your-app-name"
        PORT = "3000"
    }

    stages {

        stage('Checkout Code') {
            steps {
                git branch: 'main',
                    url: 'https://github.com/YOUR_ORG/your-repo.git'
            }
        }

        stage('Build Docker Image') {
            steps {
                sh '''
                docker build -t $APP_NAME:latest .
                '''
            }
        }

        stage('Stop Old Container') {
            steps {
                sh '''
                docker stop $APP_NAME || true
                docker rm $APP_NAME || true
                '''
            }
        }

        stage('Run New Container') {
            steps {
                sh '''
                docker run -d \
                  --name $APP_NAME \
                  -p 3000:3000 \
                  --restart always \
                  $APP_NAME:latest
                '''
            }
        }
    }

    post {
        success {
            echo "✅ Deployment successful"
        }
        failure {
            echo "❌ Deployment failed"
        }
    }
}

Important

Commit and push this file to your repository before proceeding.

Step 5: Configure Pipeline Job

Open your job:

your-pipeline-name → Configure

In the Pipeline section, configure:

Field	Value
Definition	Pipeline script from SCM
SCM	Git
Repository URL	Your repo URL
Credentials	github-creds (if private)
Branch	main
Script Path	Jenkinsfile

Click Save

Step 6: Build & Verify

Trigger Build

Click Build Now

Verify Console Output

Open Console Output and verify each stage:

[x] Code checkout
[x] Docker build
[x] Old container stopped
[x] New container running

Verify on Server

docker ps

You should see:

your-app-name   Up   0.0.0.0:3000->3000

Step 7: Access Application

Open in browser:

http://SERVER_IP:3000

Or if Nginx is configured:

http://frontend.yourdomain.com

Step 8: Auto Deploy with Webhook

Configure GitHub Webhook

Go to your GitHub repository:

Repo → Settings → Webhooks → Add webhook

Configure:

Field	Value
Payload URL	`https://jenkins.yourdomain.com/github-webhook/`
Content type	application/json
Events	Push

Click Save

Now every git push will automatically trigger Jenkins deployment!

Step 9: Optional - Nginx + SSL

Recommended production flow:

Domain → Nginx (443 SSL) → localhost:3000

Nginx Configuration

Create /etc/nginx/sites-available/frontend:

server {
    listen 80;
    server_name frontend.yourdomain.com;

    location / {
        proxy_pass http://localhost:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;
    }
}

Enable the site:

sudo ln -s /etc/nginx/sites-available/frontend /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

Install SSL with Certbot

sudo apt install certbot python3-certbot-nginx -y
sudo certbot --nginx -d frontend.yourdomain.com

Final Checklist

Task	Status
Jenkins via Docker	✅
Pipeline configured	✅
Docker build & run	✅
Auto-deploy ready	✅
Domain accessible	✅
SSL configured	✅

Troubleshooting

Jenkins can't access Docker

docker exec -it jenkins bash
docker ps

If permission denied, run:

docker exec -u root jenkins chmod 666 /var/run/docker.sock

Build fails at checkout

Verify repository URL is correct
Check credentials if repo is private
Ensure branch name matches

Container not starting

Check logs:

docker logs your-app-name

Your Jenkins CI/CD pipeline is now fully configured!