One‑Click Deployment of Branch Code to a Remote Server Using Jenkins

Background : A new project lacked an automated deployment pipeline, so a Jenkins‑based solution was built to pull a GitLab branch, build a Java JAR, back up the existing JAR on the target server, copy the new JAR, and restart Docker services.

Jenkins Installation : Download Jenkins from https://www.jenkins.io/download/ and follow the official installation guide at https://www.jenkins.io/doc/book/installing/. After installation, open the Jenkins dashboard.

Global Tool Configuration : In Manage Jenkins → Global Tool Configuration , add the Java JDK and Maven installations so Jenkins can compile the project.

Project Creation : Create a Freestyle Project named (e.g., passjava‑dev). Configure the source code management section with the GitLab repository URL, username, and password.

Build Steps :

Execute shell:

echo "开始打包"
 mvn clean package
 echo "打包完成"

Running the build (click Build Now ) pulls the code, runs mvn clean package, and produces a JAR located at C:\ProgramData\Jenkins.jenkins\workspace\passjava‑dev. The console output shows the build duration (e.g., 2 min 33 s) and a Finished: SUCCESS status.

Publish Over SSH Plugin : Install the “Publish Over SSH” plugin via Manage Jenkins → Plugin Manager → Available . Configure a global SSH server with hostname, username, password/key, and remote directory.

Backup Existing JAR on the remote server:

Create a bak directory.

Create a timestamped sub‑directory inside bak.

Rename the current JAR to original‑timestamp.jar.

Copy New JAR to the remote server using the SSH plugin, specifying the workspace JAR path (e.g.,

C:\ProgramData\Jenkins.jenkins\workspace\<project>\target\app.jar

) and the remote target directory.

Rolling Update with Docker Swarm :

On the remote server, a restart.sh script is executed via SSH:

echo "部署 jar 包"
cd /nfs-data/wukong/
nohup sudo sh restart.sh
exit

The restart.sh script forces updates of Docker services:

echo "部署 passjava 服务"
nohup sudo docker service update accountservice --force > /nfs-data/wukong/jenkins/account.txt
nohup sudo docker service update gatewayservice --force > /nfs-data/wukong/jenkins/gateway.txt
nohup sudo docker service update qmsservice --force > /nfs-data/wukong/jenkins/qms.txt

Problems Encountered and Solutions :

Git SSL certificate error : Disable SSL verification with

git config --system http.sslVerify false
git config --global http.sslVerify false

SSH timeout : Increase the timeout setting in the SSH plugin configuration.

Permission issues : Configure sudoers on the remote host so the Jenkins user can run Docker commands without a password.

After addressing these issues, the pipeline completes with Finished: SUCCESS, confirming that the JAR is built, transferred, and the Docker services are updated automatically.