When faced with repetitive technical tasks, finding automation solutions that work can be a chore. With Jenkins, an open-source automation server, you can efficiently manage tasks from building to deploying software. Jenkins is Java-based, installed from Ubuntu packages or by downloading and running its web application archive (WAR) file — a collection of files that make up a complete web application to run on a server.
In this tutorial we’ll install Jenkins on Ubuntu 20.04, start the development server and create an administrative user to get you started in exploring what Jenkins can do.
To follow this tutorial, you will need:
- One Ubuntu 20.04 server configured with a non-root sudo user and firewall by following the Ubuntu 20.04 initial server setup guide. We recommend starting with at least 1 GB of RAM. Visit Jenkins’s “Hardware Recommendations” for guidance in planning the capacity of a production-level Jenkins installation.
- Oracle JDK 11 installed, following our guidelines on installing specific versions of OpenJDK on Ubuntu 20.04.
Step 1 — Installing Jenkins
The version of Jenkins included with the default Ubuntu packages is often behind the latest available version from the project itself. To ensure you have the latest fixes and features, use the project-maintained packages to install Jenkins.
First, add the repository key to the system:
wget -q -O - https://pkg.jenkins.io/debian-stable/jenkins.io.key | sudo apt-key add -
After the key is added the system will return with
Next, let’s append the Debian package repository address to the server’s
sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'
After both commands have been entered, we’ll run
update so that
apt will use the new repository.
sudo apt update
Finally, we’ll install Jenkins and its dependencies.
sudo apt install jenkins
Now that Jenkins and its dependencies are in place, we’ll start the Jenkins server.
Step 2 — Starting Jenkins
Let’s start Jenkins by using
sudo systemctl start jenkins
systemctl doesn’t display status output, we’ll use the
status command to verify that Jenkins started successfully:
sudo systemctl status jenkins
If everything went well, the beginning of the status output shows that the service is active and configured to start at boot:
Output● jenkins.service - LSB: Start Jenkins at boot time Loaded: loaded (/etc/init.d/jenkins; generated) Active: active (exited) since Fri 2020-06-05 21:21:46 UTC; 45s ago Docs: man:systemd-sysv-generator(8) Tasks: 0 (limit: 1137) CGroup: /system.slice/jenkins.service
Now that Jenkins is up and running, let’s adjust our firewall rules so that we can reach it from a web browser to complete the initial setup.
Step 3 — Opening the Firewall
To set up a UFW firewall, visit Initial Server Setup with Ubuntu 20.04, Step 4- Setting up a Basic Firewall. By default, Jenkins runs on port
8080. We’ll open that port using
sudo ufw allow 8080
Note: If the firewall is inactive, the following commands will allow OpenSSH and enable the firewall:
sudo ufw allow OpenSSH sudo ufw enable
ufw’s status to confirm the new rules:
sudo ufw status
You’ll notice that traffic is allowed to port
8080 from anywhere:
OutputStatus: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere 8080 ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6) 8080 (v6) ALLOW Anywhere (v6)
With Jenkins installed and our firewall configured, we can complete the installation stage and dive into Jenkins setup.
Step 4 — Setting Up Jenkins
To set up your installation, visit Jenkins on its default port,
8080, using your server domain name or IP address:
You should receive the Unlock Jenkins screen, which displays the location of the initial password.
In the terminal window, use the
cat command to display the password:
sudo cat /var/lib/jenkins/secrets/initialAdminPassword
Copy the 32-character alphanumeric password from the terminal and paste it into the Administrator password field, then click Continue.
The next screen presents the option of installing suggested plugins or selecting specific plugins.
We’ll click the Install suggested plugins option, which will immediately begin the installation process.
When the installation is complete, you’ll be prompted to set up the first administrative user. It’s possible to skip this step and continue as
admin using the initial password we used above, but we’ll take a moment to create the user.
Note: The default Jenkins server is NOT encrypted, so the data submitted with this form is not protected.
Enter the name and password for your user.
You’ll receive an Instance Configuration page that will ask you to confirm the preferred URL for your Jenkins instance. Confirm either the domain name for your server or your server’s IP address.
After confirming the appropriate information, click Save and Finish. You’ll receive a confirmation page confirming that “Jenkins is Ready!”:
Click Start using Jenkins to visit the main Jenkins dashboard.
At this point, you have completed a successful installation of Jenkins.
In this tutorial, you installed Jenkins using the project-provided packages, started the server, opened the firewall, and created an administrative user. At this point, you can start exploring Jenkins.