Java Docker Pipeline Project

This project demonstrates a Java application built and deployed using a Docker pipeline within a Jenkins environment. The final Docker image is hosted on Docker Hub: Java App Pipeline Image.

Prerequisites

• Docker: Install and run Docker from here.
• Java 11 or later: Required JDK for the project.
• Maven: Install Maven from here.
• Jenkins: A Jenkins server is required to execute the CI/CD pipeline.

Getting Started

1. Set Up Your Virtual Machines:

   • Install Ubuntu on Both VMs:
     • Download the Ubuntu ISO and create two VMs in VMware Workstation.
     • Install Ubuntu on both VMs.
   • Install Required Software:
     • On both VMs, update the package list and install the necessary packages:

     sudo apt update
     sudo apt install openjdk-17-jdk git docker.io

2. Set Up Jenkins on VM1 (Jenkins Master):

   • Add the Jenkins repository and install Jenkins:

     wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -
     sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'
     sudo apt update
     sudo apt install jenkins

   • Start Jenkins:
     • Start Jenkins and enable it to start on boot:

     sudo systemctl start jenkins
     sudo systemctl enable jenkins

   • Access Jenkins:
     • Open a web browser and go to http://<VM1_IP>:8080.
     • Follow the setup instructions to unlock Jenkins and install suggested plugins.

3. Configure Jenkins Agent on VM2:

   • Create a Jenkins User:

     • On VM2, create a user for Jenkins:

     sudo useradd -m -s /bin/bash
     sudo passwd jenkins

   • Install Java and Docker.

   • Set Up SSH Key:

     • Generate an SSH key on VM1 and copy it to VM2:

     ssh-keygen
     ssh-copy-id jenkins@<VM2_IP>

     

   • Configure Jenkins Agent:

     • In Jenkins (VM1), add VM2 as a new node and configure it to connect via SSH using the Jenkins user.

4. Clone the Repository on VM1:

   • Clone the Repository:
     • On VM1, clone the repository:

     https://github.com/omarMohamedo-o/depi_final_project.git

5. Modify the Front Page:

   • Navigate to the Views Directory:
     • Go to the views directory of the cloned repository:

     cd depi_final_project/views

   • Modify home.pug:
     • Edit home.pug to display your group code:

     vim home.pug

     

6. Jenkins Setup

   • In the root directory of the cloned repository, create a Jenkinsfile:
   • Configure Jenkins with necessary plugins (e.g., Pipeline, Docker).
   • Create a new Jenkins pipeline job.
   • Point the job to the Jenkinsfile in this repository.
   • Set up credentials for Docker Hub if you plan to push the image.

7. Run the Jenkins Pipeline:

   • Manually trigger a build in Jenkins.
   • The pipeline will execute the steps defined in the Jenkinsfile.
   • Monitor the stages to ensure everything runs smoothly.

Project Structure

• src/main/java/com/example: Java source code.
• src/main/resources: Configuration files.
• Dockerfile: Instructions for Docker image creation.
• Jenkinsfile: Defines pipeline stages for Jenkins.

Pipeline Stages

• Build: Compile the Java code into a JAR file.
• Test: Optionally run unit or integration tests.
• Docker Build: Build the Docker image using the Dockerfile.
• Docker Push: Push the built image to Docker Hub.
• Deploy: Optionally define deployment steps (currently omitted).

Customization

• Application Code: Modify Java files in src to change app functionality.
• Dockerfile: Adjust base image, dependencies, or installation steps as needed.
• Jenkinsfile: Tailor pipeline stages to fit your specific CI/CD workflow.

Challenges and Resolutions

• JAVA_HOME Issue on Jenkins Agent:

  • Issue: UnsupportedClassVersionError due to incorrect JAVA_HOME setting on the Jenkins agent.
  • Solution: Correct JAVA_HOME in Jenkins agent configuration to point to the JDK 11+ directory.

• Docker Hub Credentials in Jenkins:

  • Issue: Pipeline failed to push the image due to missing credentials.
  • Solution: Add Docker Hub credentials to Jenkins and configure the job to use them via the withCredentials block.

Docker Hub Image

You can find the final Docker image on Docker Hub: Java App Pipeline.

Contributing

Contributions are welcome! Feel free to open issues or submit pull requests.