Build a Simple Jenkins CI/CD Pipeline with Maven and Git

1. Prerequisites

Three servers are required:

GitLab server: IP 192.168.40.99, 8C8G, software: gitlab

Jenkins server: IP 192.168.40.98, 4C4G, software: jenkins, jdk, maven, git

Test server: IP 192.168.40.97, 2C2G, software: jdk

Install the listed software on each machine.

2. Environment Preparation

2.1 Create a blank project in GitLab

Navigate to Your work / Groups / New group and create a group.

Inside the group click Create group.

Create a new project by clicking New project and choose a blank project.

Enter a project name and click Create project.

Generate a personal access token (e.g., glpat-xxxx) in Preferences → Access Tokens and copy it.

2.2 Create a new project in IDEA

Open IDEA → Settings → Git and set the path to the local Git executable.

Create a Git repository for the project.

3. Jenkins CI/CD

3.1 Install Maven plugin

In Jenkins go to

Dashboard → Manage Jenkins → Plugin Management → Available Plugins

, search for "maven" and install it.

3.2 Create a Jenkins job

Click Dashboard → All → New Item, give the job a name (e.g., first) and select a Freestyle project.

3.3 Configure Git

In the job configuration set the Git repository URL (using the token) and add the credentials.

3.4 Configure branch

Specify the branch to build (e.g., */main).

3.5 Configure Maven

Set Maven installation path at http://192.168.40.98:8080/configureTools/. Keep the Root POM as jenkins-study/pom.xml.

3.6 Test Jenkins build

Save the configuration and click Build Now. The console output shows the JAR file generated in /root/.jenkins/workspace/first/target/. Run it with: java -jar jenkins-study-0.0.1-SNAPSHOT.jar If you see the error "no main manifest attribute", set skip to false in the spring-boot-maven-plugin configuration.

3.7 Install SSH Publisher plugin

Install the "SSH Publisher" plugin via Manage Jenkins → Plugin Management → Available Plugins.

3.8 Configure test server in Jenkins

Go to Manage Jenkins → System and add a new SSH server with the test machine’s IP, username, and private key. Test the connection.

3.9 Configure Post‑Build Steps

In Post Steps → Send files or execute commands over SSH set:

Source files : **/jenkin*.jar (any JAR in the workspace)

Remote directory : ~ (or /root for root user)

Optionally enable "Remove prefix" to avoid creating a /target sub‑directory on the remote host.

3.10 Configure Pre‑Build Steps (cleanup script)

Create a clean.sh script on the test server:

#!/bin/bash
appname=$1
if [ -z $appname ]; then
  echo "Application name cannot be empty!"
  exit -1
else
  echo "Application name is $1"
fi
# Remove old JARs
rm -rf $appname/*.jar
# Find running PID
pid=$(ps -ef | grep $1 | grep 'java -jar' | awk '{printf $2}')
if [ -z $pid ]; then
  echo "$appname is not started"
else
  kill -9 $pid
  echo "$appname was stopped"
fi

Make it executable ( chmod 777 clean.sh) and add it to Jenkins Pre Steps as sh clean.sh jenkins-study.

3.11 Run the pipeline

Build the job. The pre‑step script stops any previous instance and removes old JARs, then the Maven build creates a new JAR, and the post‑step publishes it to the test server. Verify the process with jps and access the application at http://192.168.40.97:8088.

4. Summary

The tutorial demonstrates a complete Jenkins CI/CD pipeline for a simple Spring Boot application, including source control, build, artifact publishing, and cleanup. Consider further improvements such as parallel stages, automated testing, and containerization.