Build, Tag & Push Docker Image to Docker Hub using Jenkins Pipeline

🎯 Objective

• Build a Docker image for a Node.js app using Jenkins

• Tag the image dynamically with build number or commit ID

• Push the image to Docker Hub

• Automate everything via a Jenkins Pipeline

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🧰 Tools Used

• Amazon Linux 2 EC2

• Git, GitHub

• Docker

• Jenkins

• Docker Hub

• Node.js App Repo: https://github.com/suneelprojects/nodejs-project-docker.git

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🪜 Step-by-Step Procedure

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1️⃣ Fork the Repo (If not done already)

Go to 👉 https://github.com/suneelprojects/nodejs-project-docker.git
Click Fork and work on your copy.

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2️⃣ Install Docker on EC2 (if not already installed)

sudo yum update -y
sudo amazon-linux-extras enable docker
sudo yum install docker -y
sudo service docker start
sudo usermod -aG docker ec2-user

🚨 Reboot instance or re-login after usermod.

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3️⃣ Install Jenkins on EC2 (if not already installed)

(Skip if already installed. Let me know if you want installation steps again.)

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4️⃣ Create Docker Hub Credentials in Jenkins

• Go to Jenkins Dashboard → Manage Jenkins → Credentials → (global)

• Add Username and Password for Docker Hub

• ID: dockerhub

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5️⃣ Create Jenkins Pipeline Job

• Go to Jenkins → New Item → dockerhub-push-pipeline → Type: Pipeline

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6️⃣ Use this Jenkins Pipeline Script

pipeline {
    agent any

    environment {
        DOCKER_HUB_CREDENTIALS = credentials('dockerhub')
        IMAGE_NAME = 'yourdockerhubusername/nodejs-app'
        TAG = "v${BUILD_NUMBER}"
    }

    stages {
        stage('Clone Repo') {
            steps {
                git 'https://github.com/<your-username>/nodejs-project-docker.git'
            }
        }

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

        stage('Login to Docker Hub') {
            steps {
                sh "echo $DOCKER_HUB_CREDENTIALS_PSW | docker login -u $DOCKER_HUB_CREDENTIALS_USR --password-stdin"
            }
        }

        stage('Push Image to Docker Hub') {
            steps {
                sh 'docker push $IMAGE_NAME:$TAG'
            }
        }

        stage('Logout') {
            steps {
                sh 'docker logout'
            }
        }
    }
}

✅ Replace yourdockerhubusername with your actual Docker Hub username.
This pipeline will tag the image as v1, v2, etc., based on Jenkins build number.

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🔎 Understanding the Flow (How it works – In-Depth)