Revamp Academy Docs

Goal

Build a complete CI/CD pipeline:

GitHub
   ↓
Jenkins
   ↓
Checkout
   ↓
Install & Test
   ↓
Build Docker Image
   ↓
Push to Docker Hub
   ↓
Deploy Application

Sample project:

https://github.com/VenkatMastercoder/jenkins-cicd-projects/tree/master/project-3-cicd-docker-deploy

Prerequisites

Docker installed on the EC2 host
A Docker Hub account
Jenkins credential ID dockerhub-credentials (previous lesson)
GitHub webhook optional but recommended

Application structure

project-3-cicd-docker-deploy/
├── .dockerignore
├── .gitignore
├── index.js
├── index.test.js
├── Jenkinsfile
├── Dockerfile
├── package-lock.json
└── package.json

Example Dockerfile pattern:

FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install --production
COPY . .
EXPOSE 3000
CMD ["node", "index.js"]

Adjust COPY / CMD to match the real project layout in the repo.

Example CI/CD Jenkinsfile

pipeline {
  agent any
 
  environment {
    DOCKER_IMAGE = "yourdockerhubusername/my-app"
    DOCKER_TAG   = "${BUILD_NUMBER}"
    DOCKER_CREDENTIALS = 'dockerhub-credentials'
    EMAIL_TO = "your-email@gmail.com"
  }
 
  stages {
    stage('Checkout') {
      steps {
        echo "Pulling latest code..."
        checkout scm
      }
    }
 
    stage('Install & Test') {
      agent {
        docker { image 'node:18-alpine' }
      }
      steps {
        dir('project-3-cicd-docker-deploy') {
          sh 'npm install'
          sh 'npm test'
        }
      }
    }
 
    stage('Build Docker Image') {
      steps {
        dir('project-3-cicd-docker-deploy') {
          sh "docker build -t ${DOCKER_IMAGE}:${DOCKER_TAG} ."
          sh "docker tag ${DOCKER_IMAGE}:${DOCKER_TAG} ${DOCKER_IMAGE}:latest"
        }
      }
    }
 
    stage('Push to Docker Hub') {
      steps {
        withCredentials([usernamePassword(
          credentialsId: "${DOCKER_CREDENTIALS}",
          usernameVariable: 'DOCKER_USER',
          passwordVariable: 'DOCKER_PASS'
        )]) {
          sh 'echo $DOCKER_PASS | docker login -u $DOCKER_USER --password-stdin'
          sh "docker push ${DOCKER_IMAGE}:${DOCKER_TAG}"
          sh "docker push ${DOCKER_IMAGE}:latest"
        }
      }
    }
 
    stage('Deploy') {
      steps {
        sh """
          docker stop my-app || true
          docker rm my-app || true
 
          docker run -d \
            --name my-app \
            -p 3003:3000 \
            --restart unless-stopped \
            ${DOCKER_IMAGE}:${DOCKER_TAG}
        """
      }
    }
  }
 
  post {
    success {
      mail(
        to: "${EMAIL_TO}",
        subject: "SUCCESS: ${env.JOB_NAME} #${env.BUILD_NUMBER}",
        body: "Deployed ${DOCKER_IMAGE}:${DOCKER_TAG}\n${env.BUILD_URL}"
      )
    }
    failure {
      mail(
        to: "${EMAIL_TO}",
        subject: "FAILURE: ${env.JOB_NAME} #${env.BUILD_NUMBER}",
        body: "Check logs: ${env.BUILD_URL}"
      )
    }
    always {
      sh 'docker logout || true'
      sh 'docker image prune -f || true'
    }
  }
}

Set DOCKER_IMAGE and EMAIL_TO to your values. Align ports with the project's Dockerfile/EXPOSE.

Step 1 — Create the Pipeline job

New Item → name project-3-docker-cicd → Pipeline → OK
Definition: Pipeline script from SCM
SCM: Git → repo URL → credentials → branch */master
Script Path: project-3-cicd-docker-deploy/Jenkinsfile
Enable GitHub hook trigger for GITScm polling
Save → Build Now

Docker integration checklist

Step	Command / action
Dockerfile	Defines runtime image
Docker build	`docker build -t name:tag .`
Docker tag	Also tag `:latest`
Docker login	`withCredentials` + `--password-stdin`
Docker push	Push version tag + latest
Deploy	`docker stop/rm` old container → `docker run` new
Cleanup	`docker logout`, prune dangling images

Possible error — Docker-in-Docker

First builds often fail on Build Docker Image with:

docker: not found
script returned exit code 127
Finished: FAILURE

Console failure — docker: not found inside the Jenkins container

Why?

Jenkins runs inside a container. docker build looks for the Docker CLI inside that container, not on the EC2 host.

EC2 Ubuntu Host   ← Docker is installed here
    └── Jenkins Container
            └── docker build   ← not found

Fix — mount the host Docker socket

You do not need a nested Docker daemon. Share the host daemon with Jenkins.

1. Stop and remove the current container (configs stay in the volume):

docker stop jenkins
docker rm jenkins

2. Re-run with socket + CLI mounts:

docker run -d \
  --name jenkins \
  -p 8080:8080 \
  -p 50000:50000 \
  -p 3001:3001 \
  -v jenkins_home:/var/jenkins_home \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v $(which docker):/usr/bin/docker \
  jenkins/jenkins:lts

Flag	Purpose
`-v /var/run/docker.sock:/var/run/docker.sock`	Share host Docker daemon
`-v $(which docker):/usr/bin/docker`	Provide Docker CLI binary

3. Fix socket permissions:

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

4. Verify:

docker exec jenkins docker ps

docker ps from inside Jenkins after mounting the host socket

If you see containers listed, the pipeline can docker build, push, and run via the EC2 engine.

EC2 Ubuntu Host   ← Docker daemon
    └── Jenkins Container
            └── docker build  → host daemon via socket
            └── docker run    → container runs on EC2

Recreating the container drops packages installed inside it. Reinstall Node.js/PM2 only if Freestyle jobs still need them:

docker exec -u root -it jenkins bash
apt update && apt install nodejs npm -y
npm install -g pm2
exit

Re-run and access the app

Build Now (or push a commit if webhook is set)
Confirm stages: Checkout → Install & Test → Build → Push → Deploy

All Project 3 pipeline stages green

Open:

http://<your-ec2-public-ip>:3003

(Use the host port you mapped in docker run.)

Deployed app reachable on the EC2 public IP

Full flow

Code Push
   ↓
GitHub Webhook
   ↓
Jenkins Pipeline
   ↓
Install + Test
   ↓
Build Docker Image
   ↓
Push to Docker Hub
   ↓
Deploy Container
   ↓
Live Application

You now have Jenkins + GitHub + Docker CI/CD. Day 4 adds Multibranch (when per branch), Master–Agent, and credential security practices.

Goal

Build a complete CI/CD pipeline:

GitHub
   ↓
Jenkins
   ↓
Checkout
   ↓
Install & Test
   ↓
Build Docker Image
   ↓
Push to Docker Hub
   ↓
Deploy Application

Sample project:

https://github.com/VenkatMastercoder/jenkins-cicd-projects/tree/master/project-3-cicd-docker-deploy

Prerequisites

Docker installed on the EC2 host
A Docker Hub account
Jenkins credential ID dockerhub-credentials (previous lesson)
GitHub webhook optional but recommended

Application structure

project-3-cicd-docker-deploy/
├── .dockerignore
├── .gitignore
├── index.js
├── index.test.js
├── Jenkinsfile
├── Dockerfile
├── package-lock.json
└── package.json

Example Dockerfile pattern:

FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install --production
COPY . .
EXPOSE 3000
CMD ["node", "index.js"]

Adjust COPY / CMD to match the real project layout in the repo.

Example CI/CD Jenkinsfile

pipeline {
  agent any
 
  environment {
    DOCKER_IMAGE = "yourdockerhubusername/my-app"
    DOCKER_TAG   = "${BUILD_NUMBER}"
    DOCKER_CREDENTIALS = 'dockerhub-credentials'
    EMAIL_TO = "your-email@gmail.com"
  }
 
  stages {
    stage('Checkout') {
      steps {
        echo "Pulling latest code..."
        checkout scm
      }
    }
 
    stage('Install & Test') {
      agent {
        docker { image 'node:18-alpine' }
      }
      steps {
        dir('project-3-cicd-docker-deploy') {
          sh 'npm install'
          sh 'npm test'
        }
      }
    }
 
    stage('Build Docker Image') {
      steps {
        dir('project-3-cicd-docker-deploy') {
          sh "docker build -t ${DOCKER_IMAGE}:${DOCKER_TAG} ."
          sh "docker tag ${DOCKER_IMAGE}:${DOCKER_TAG} ${DOCKER_IMAGE}:latest"
        }
      }
    }
 
    stage('Push to Docker Hub') {
      steps {
        withCredentials([usernamePassword(
          credentialsId: "${DOCKER_CREDENTIALS}",
          usernameVariable: 'DOCKER_USER',
          passwordVariable: 'DOCKER_PASS'
        )]) {
          sh 'echo $DOCKER_PASS | docker login -u $DOCKER_USER --password-stdin'
          sh "docker push ${DOCKER_IMAGE}:${DOCKER_TAG}"
          sh "docker push ${DOCKER_IMAGE}:latest"
        }
      }
    }
 
    stage('Deploy') {
      steps {
        sh """
          docker stop my-app || true
          docker rm my-app || true
 
          docker run -d \
            --name my-app \
            -p 3003:3000 \
            --restart unless-stopped \
            ${DOCKER_IMAGE}:${DOCKER_TAG}
        """
      }
    }
  }
 
  post {
    success {
      mail(
        to: "${EMAIL_TO}",
        subject: "SUCCESS: ${env.JOB_NAME} #${env.BUILD_NUMBER}",
        body: "Deployed ${DOCKER_IMAGE}:${DOCKER_TAG}\n${env.BUILD_URL}"
      )
    }
    failure {
      mail(
        to: "${EMAIL_TO}",
        subject: "FAILURE: ${env.JOB_NAME} #${env.BUILD_NUMBER}",
        body: "Check logs: ${env.BUILD_URL}"
      )
    }
    always {
      sh 'docker logout || true'
      sh 'docker image prune -f || true'
    }
  }
}

Set DOCKER_IMAGE and EMAIL_TO to your values. Align ports with the project's Dockerfile/EXPOSE.

Step 1 — Create the Pipeline job

New Item → name project-3-docker-cicd → Pipeline → OK
Definition: Pipeline script from SCM
SCM: Git → repo URL → credentials → branch */master
Script Path: project-3-cicd-docker-deploy/Jenkinsfile
Enable GitHub hook trigger for GITScm polling
Save → Build Now

Docker integration checklist

Step	Command / action
Dockerfile	Defines runtime image
Docker build	`docker build -t name:tag .`
Docker tag	Also tag `:latest`
Docker login	`withCredentials` + `--password-stdin`
Docker push	Push version tag + latest
Deploy	`docker stop/rm` old container → `docker run` new
Cleanup	`docker logout`, prune dangling images

Possible error — Docker-in-Docker

First builds often fail on Build Docker Image with:

docker: not found
script returned exit code 127
Finished: FAILURE

Console failure — docker: not found inside the Jenkins container

Why?

Jenkins runs inside a container. docker build looks for the Docker CLI inside that container, not on the EC2 host.

EC2 Ubuntu Host   ← Docker is installed here
    └── Jenkins Container
            └── docker build   ← not found

Fix — mount the host Docker socket

You do not need a nested Docker daemon. Share the host daemon with Jenkins.

1. Stop and remove the current container (configs stay in the volume):

docker stop jenkins
docker rm jenkins

2. Re-run with socket + CLI mounts:

docker run -d \
  --name jenkins \
  -p 8080:8080 \
  -p 50000:50000 \
  -p 3001:3001 \
  -v jenkins_home:/var/jenkins_home \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v $(which docker):/usr/bin/docker \
  jenkins/jenkins:lts

Flag	Purpose
`-v /var/run/docker.sock:/var/run/docker.sock`	Share host Docker daemon
`-v $(which docker):/usr/bin/docker`	Provide Docker CLI binary

3. Fix socket permissions:

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

4. Verify:

docker exec jenkins docker ps

docker ps from inside Jenkins after mounting the host socket

If you see containers listed, the pipeline can docker build, push, and run via the EC2 engine.

EC2 Ubuntu Host   ← Docker daemon
    └── Jenkins Container
            └── docker build  → host daemon via socket
            └── docker run    → container runs on EC2

Recreating the container drops packages installed inside it. Reinstall Node.js/PM2 only if Freestyle jobs still need them:

docker exec -u root -it jenkins bash
apt update && apt install nodejs npm -y
npm install -g pm2
exit

Re-run and access the app

Build Now (or push a commit if webhook is set)
Confirm stages: Checkout → Install & Test → Build → Push → Deploy

All Project 3 pipeline stages green

Open:

http://<your-ec2-public-ip>:3003

(Use the host port you mapped in docker run.)

Deployed app reachable on the EC2 public IP

Full flow

Code Push
   ↓
GitHub Webhook
   ↓
Jenkins Pipeline
   ↓
Install + Test
   ↓
Build Docker Image
   ↓
Push to Docker Hub
   ↓
Deploy Container
   ↓
Live Application

You now have Jenkins + GitHub + Docker CI/CD. Day 4 adds Multibranch (when per branch), Master–Agent, and credential security practices.

Project 3 — Full CI/CD with Docker

Goal

Prerequisites

Application structure

Example CI/CD Jenkinsfile

Step 1 — Create the Pipeline job

Docker integration checklist

Possible error — Docker-in-Docker

Why?

Fix — mount the host Docker socket

Re-run and access the app

Full flow

Project 3 — Full CI/CD with Docker

Goal

Prerequisites

Application structure

Example CI/CD Jenkinsfile

Step 1 — Create the Pipeline job

Docker integration checklist

Possible error — Docker-in-Docker

Why?

Fix — mount the host Docker socket

Re-run and access the app

Full flow