Jenkins is one of the most popular open-source automation/build servers with a lot of plugins to support building, deploying, and automating any project.

Prerequisites

• Java 11

Install Jenkins

Installing jenkins from repository in ubuntu 16.04.6 server requires repository list modification to install and receive updates for Jenkins itself. To start the installation process we need to add the jenkins official repository key to the system

wget -q -O - https://pkg.jenkins.io/debian/jenkins-ci.org.key | sudo apt-key add -

When the key is added to the system, it will return OK.

Next, we will add jenkins repository to the system’s repository list

echo deb https://pkg.jenkins.io/debian-stable binary/ | sudo tee /etc/apt/sources.list.d/jenkins.list

Once the repository has been added to the system list, we will update the repository index by running

sudo apt-get update

This will update the system repository index and jenkins repository will be used by apt-get. Finally, We will install jenkins itself and its dependencies

sudo apt-get -y install jenkins

Now that Jenkins and its dependencies are in place, we can start the Jenkins server. Using systemctl we can start jenkins

sudo systemctl start jenkins

To check the status of jenkins use

sudo systemctl status jenkins

If everything is okay and Jenkins started properly, the output should be something like below

● jenkins.service - LSB: Start Jenkins at boot time
Loaded: loaded (/etc/init.d/jenkins; bad; vendor preset: enabled)
Active: active (exited) since Fri 2019-04-26 12:02:46 CEST; 5min ago
  Docs: man:systemd-sysv-generator(8)

Setup Jenkins

Once the Jenkins service is up and running. Open a browser and type the following in the address bar

http://<your_sever_ip>:8080

This will open the Jenkins installation window. For the first use, it will ask for authentication (see the image below)

After authentication, follow on-screen instructions to set up Jenkins

Bind Jenkins to 127.0.0.1

Jenkins can be bound to listen to a specific host by modifying the default Jenkins configuration file located at /etc/default/jenkins in Ubuntu systems.

Add a variable to the file called HTTP_HOST=127.0.0.1 then pass it as a value of the argument flag --httpListenAddress for JENKINS_ARGS

JENKINS_ARGS="--webroot=/var/cache/$NAME/war --httpPort=$HTTP_PORT --httpListenAddress=$HTTP_HOST"

Fix jenkins User Pemissions

To make sure that jenkins user can access/have appropriate rights to run all the commands necessary, first run

sudo visudo

The file will be opened with vi editor. If you want to open the file in any other editor like nano use the following syntax

sudo EDITOR="nano" visudo

Add the following line to the sudoers file and save (ctrl+o and ctrl+x) it.

jenkins ALL=(ALL) NOPASSWD: ALL

After exit, restart/reboot or log out and log in to the system to apply these settings.

Enjoy!