How to Install Jenkins on CentOS 8/RHEL 8

In this article, We are going to perform How to Install Jenkins on CentOS 8/RHEL 8 or any other cloud platform like Amazon EC2, Azure VM, Google Cloud Compute,etc. with preinstalled CentOS 8/RHEL 8.

Introduction

Jenkins is an opensource automation tool which is used for continuous integration. Some of below features of Jenkins

  1. Jenkins can be used as a simple CI server or turned into the continuous delivery hub for any project.
  2. Easy installation
  3. Easy configuration
  4. It provides 400+ Pulgin
  5. Jenkins provides extensible features by adding plugins and distributed by build different projects and testing etc.

Prerequisites

  • CentOS 8
  • Atleast 1 GB RAM
  • JDK 1.8 or Higher verison is supported
  • Open Port 8080

Install JDK on Ubuntu

Please follow below article to download and install Oracle JAVA 11 on CentOS 8 Manually

Download and Install Oracle Java 11 on CentOS 8

OR

You can install Open JDK 11

$ sudo yum -y install java-11-openjdk-devel

Verify Java Version

To check the java version:

$ java -version

Output:

java version "11.0.6" 2020-01-14 LTS 

Java(TM) SE Runtime Environment 18.9 (build 11.0.6+8-LTS)

Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.6+8-LTS, mixed mode)

Step 1: Download and Add Jenkins GPG Key

Download and Add Jenkins LTS repo in /etc/yum.repos.d/jenkins.repo location

$ sudo wget -O /etc/yum.repos.d/jenkins.repo http://pkg.jenkins-ci.org/redhat-stable/jenkins.repo

Output:

http://pkg.jenkins-ci.org/redhat-stable/jenkins.repo

Resolving pkg.jenkins-ci.org (pkg.jenkins-ci.org)... 52.202.51.185, 40.90.4.6, 64.4.48.6, ...

Connecting to pkg.jenkins-ci.org (pkg.jenkins-ci.org)|52.202.51.185|:80... connected.

HTTP request sent, awaiting response... 200 OK

Length: 85

Saving to: ‘/etc/yum.repos.d/jenkins.repo’

/etc/yum.repos.d/jenkins.repo                   100%[====================================================================================================>]      85  --.-KB/s    in 0s

 ‘/etc/yum.repos.d/jenkins.repo’ saved [85/85]

Import Jenkins GPG Key

$ sudo rpm --import https://jenkins-ci.org/redhat/jenkins-ci.org.key

Step 2: Install Jenkins On CentOS 8/RHEL 8

Once key and repository added , update the system packages

$ sudo yum update

Now its time to Install Jenkins and its dependencies:

$ sudo yum install jenkins

Step 4: Start Jenkins Service

Once installation completed, start the Jenkins service

$ sudo systemctl start jenkins

Check the Jenkins Service

$ sudo systemctl status jenkins

Output:

jenkins.service - LSB: Jenkins Automation Server

   Loaded: loaded (/etc/rc.d/init.d/jenkins; generated)

   Active: active (running) since Fri 2020-04-03 19:53:29 EDT; 43s ago

     Docs: man:systemd-sysv-generator(8)

  Process: 20505 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=0/SUCCESS)

    Tasks: 37 (limit: 26213)

   Memory: 360.5M

   CGroup: /system.slice/jenkins.service

           └─20528 /etc/alternatives/java -Dcom.sun.akuma.Daemon=daemonized -Djava.awt.headless=true -DJENKINS_HOME=/var/lib/jenkins -jar /usr/lib/jenkins/jenkins.war --logfile=/var/log/jenkins

Allow port 8080/tcp in Firewall to Access Jenkins from remotely

$ sudo firewall-cmd --permanent --zone=public --add-port=8080/tcp
$ sudo firewall-cmd --reload

If you have installed Jenkins on Cloud Instance Allow the Port in Incoming or Network Security Group

How to check jenkins version command line in Linux

To check Jenkins version using command line in CentOS

 $ grep version /var/lib/jenkins/config.xml

Output:

grep version /var/lib/jenkins/config.xml

<?xml version='1.1' encoding='UTF-8'?>

  <version>2.222.1</version>

Step 5: Configure Jenkins

After installation of Jenkins ,successfully running Jenkins services and we will check on browser by Jenkins default port number 8080.

We can browse server IP address or domain

 http://ip_address_or_domain_name:8080.

copy the jenkins password centos 8

By hitting IP and Port on browser for the first time it will prompt for InitialAdminPassword. ssh server and type below command.

$ sudo cat /var/lib/jenkins/secrets/intialAdminPassword

Output:

9aef30398db54a53a1a81ee86dd80726

After entering it will give some key as output. Copy and Paste in the browser and Click “Continue” .

install suggested plugins on jenkins on centos 8

In the above image we select “Install Suggested Plugins”,  and progress bar will start.

wait for jenkens plugin to install on centos 8

When the Installation get successful it will prompt for another page “Create First Admin User”.  On the below page enter username,password,Email.

In the above pic you can create new user and password or you can “Continue as admin“. After configuring everything you will prompt a new page.

create first admin user account in jenkins on centos 8

Next it will ask to configure URL to access Jenkins and click on save and Finish button.

setup the url on jenkins on centos 8

Now click on “Start using Jenkins”.  It will redirect to Jenkins Dashboard:

start using jenkins on centos 8

Finally you can see Jenkins Dashboard

jenkin dashboard on centos 8

With the above steps we have performed install jenkins on centos 8/RHEL 8.

How to Completely Remove Jenkins from CentOS 8/RHEL 8

Perform below steps, If you want to uninstall jenkins from centos 8/RHEL 8

stop the jenkins service

$ sudo systemctl stop jenkins

Remove the jenkins packages from centos 8

$ sudo yum -y remove jenkins

Remove the Jenkins cache files

$ sudo rm -rf /var/cache/jenkins

Remove the Jenkins config files directory

$ sudo rm -rf /var/lib/jenkins/

clean the yum packages

$ sudo yum clean all

Conclusion

In this article, We have covered How to install Jenkins on CentOS 8/RHEL 8,  installed JDK, checked java, jenkins version and configured Jenkins.

Related Articles

How to Install Jenkins on Ubuntu 20.04 LTS

How to Install Jenkins on Ubuntu 18.04/16.04 LTS

Reference:

Jenkins official Documentation

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