Jenkins CI/CD Pipeline with Docker and GitHub

This repository demonstrates a Jenkins pipeline implementation for achieving continuous integration and continuous deployment (CI/CD) using Docker and GitHub.

Introduction

The CI/CD pipeline provided here allows you to automate the process of building, testing, and deploying your application whenever changes are pushed to the GitHub repository. Jenkins, an open-source automation server, is used as the orchestrator for the pipeline. Docker, a popular containerization platform, is utilized to manage the deployment process.

Prerequisites

Before setting up the pipeline, ensure that you have the following prerequisites:

1. An Amazon EC2 Linux machine with Jenkins, Git, and Docker installed.
2. A GitHub repository containing your application code and Dockerfile.

Project Pipeline Flowchart

The CI/CD pipeline workflow is represented as follows:

Installation Instructions

Installing Jenkins

To install Jenkins, follow these steps:

1. Ensure that your software packages are up to date on your instance by using the following command to perform a quick software update:

   sudo yum update –y

2. Add the Jenkins repository using the following command:

   sudo wget -O /etc/yum.repos.d/jenkins.repo \
       https://pkg.jenkins.io/redhat-stable/jenkins.repo

3. Import a key file from Jenkins-CI to enable installation from the package:

   sudo rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io-2023.key

4. Upgrade the system packages:

   sudo yum upgrade

5. Install Java (Amazon Linux 2):

   sudo amazon-linux-extras install java-openjdk11 -y

   Install Java (Amazon Linux 2023):

   sudo dnf install java-11-amazon-corretto -y

6. Install Jenkins:

   sudo yum install jenkins -y

7. Enable the Jenkins service to start at boot:

   sudo systemctl enable jenkins

8. Start Jenkins as a service:

   sudo systemctl start jenkins

9. You can check the status of the Jenkins service using the command:

   sudo systemctl status jenkins

Installing Docker

To install Docker, follow these steps:

1. Install Docker:

   sudo yum install docker -y

2. Enable Docker to start on system boot:

   sudo systemctl enable docker

3. Start the Docker service:

   sudo systemctl start docker

Installing Git

To install Git, follow these steps:

1. Install Git:

   sudo yum install git -y

Additional Configuration

To allow Jenkins to interact with Docker, execute the following command:

sudo usermod -aG docker jenkins

After executing the above command, restart Jenkins:

sudo systemctl restart jenkins

Pipeline Overview

The Jenkins pipeline is triggered by a webhook configured on the GitHub repository. Whenever a developer pushes changes to the repository, the pipeline is initiated, and the following steps are executed:

1. The pipeline checks if there is a running Docker container for the application.
2. If a container is running, the pipeline copies the updated files from the Jenkins workspace to the running container, ensuring the changes are immediately reflected.
3. If no running container is found, the pipeline builds a new Docker image using the code from the GitHub repository and deploys it as a new container on the Amazon EC2 Linux machine.
4. The deployed application can then be accessed on the target machine through the specified port.

Getting Started

To get started with this CI/CD pipeline, follow the steps below:

1. Set up Jenkins, Git, and Docker on your machine.
2. Provide Jenkins with a GitHub credential (token):
   • Generate a GitHub personal access token with the appropriate scopes (repo, webhook, etc.).
   • In Jenkins, go to "Manage Jenkins" > "Manage Credentials"> "Global credentials (unrestricted)".
   • Add a new credential of type "Secret text" or "Secret file" and enter your GitHub token.
   • Save the credential.
3. Configure Jenkins by accessing its web interface.
4. Create a new Jenkins job and configure it as follows:
   • Set the job type to "Freestyle Project".
   • Connect it to your GitHub repository (https://github.com/harshartz/Jenkins-project.git) and configure the webhook.
   • Select "GitHub hook trigger for GITScm polling" as the build trigger.
   • Add an "Execute Shell" build step to the pipeline and use the following code:

   #!/bin/bash
   
    container_id=$(docker ps --filter "status=running" --format "{{.ID}}")
   
    if [ -n "$container_id" ]; then
    docker cp /var/lib/jenkins/workspace/devops-project/. "$container_id":/usr/share/nginx/html
    else
    docker build -t server /var/lib/jenkins/workspace/devops-project
    docker run -d -p 9090:80 server
    fi

Run the Jenkins job and verify the successful execution of the pipeline.

Application is running, and whenever a developer commits changes to the GitHub repository, it will automatically get deployed to the application.