Jenkins

Jenkins is an open-source automation server for building, testing, and deploying software. Its pipeline-as-code model and large plugin ecosystem let you wire up continuous integration and continuous delivery for almost any toolchain. The web UI runs on port 8080.

Software included

Component	Version
Jenkins	2.555.3 (LTS)
OpenJDK	21 (JRE)
Ubuntu	24.04 LTS

Requirements

Resource	Minimum	Recommended
vCPU	1	2
RAM	2 GB	4 GB
Storage	20 GB	50 GB

Environment variables

This image takes no deploy-time variables. It creates no shared administrator account. Jenkins generates a unique unlock password on every VM. Read it after first boot, then create your own administrator in the setup wizard:

sudo cat /var/lib/jenkins/secrets/initialAdminPassword

Getting started

1. Connect to your VM

ssh ubuntu@<your-vm-ip>

2. Wait for first-boot configuration

On the first boot, a setup script starts Jenkins, which generates a unique initial admin password for this instance. This can take a few minutes on the first start. Track progress:

journalctl -u jenkins-first-boot.service -f

The login message (MOTD) confirms when Jenkins is ready.

3. Retrieve the initial admin password

sudo cat /var/lib/jenkins/secrets/initialAdminPassword

4. Complete the setup wizard

Open a browser and navigate to:

http://<your-vm-ip>:8080

Paste the initial admin password, install the suggested plugins, and create your first administrator account.

Managing Jenkins

Jenkins runs as a systemd service.

# Check status
systemctl status jenkins

# Restart
sudo systemctl restart jenkins

# View logs
sudo journalctl -u jenkins -f

Jenkins home (jobs, plugins, and configuration): /var/lib/jenkins.

Security

Port 8080 is open on the VM’s network interface. UFW is enabled and allows SSH (port 22) and Jenkins (port 8080). No build-agent port (50000) is opened by default.

To restrict the UI to a specific IP:

sudo ufw delete allow 8080/tcp
sudo ufw allow from <trusted-ip> to any port 8080

To reach the UI without opening the firewall, use an SSH tunnel:

# Run this on your local machine
ssh -L 8080:localhost:8080 ubuntu@<your-vm-ip>

For production use, place Jenkins behind a reverse proxy such as nginx with a TLS certificate and serve the UI over HTTPS instead of exposing port 8080 directly.