Jenkins is an open source tool which is written in java. It can help us to run tasks that need to be executed once in a while. It has the ability to automatically deploy the code into the target instance whenever a developer commits changes to the source code , Hence it is referred to as CI/CD tool.

1. How to Install and Configure Jenkins on
Centos 7
Table of Contents
1. What is Jenkins
2. Features of Jenkins
3. Jenkins Architecture
4. Prerequisites
5. Installing Java
6. Installing Jenkins
7. Configuring Jenkins
What is Jenkins?
1. Jenkins is an open source tool which is written in java.

2. 2. It can help us to run tasks that need to be executed once in
a while.
3. Has the ability to automatically deploy the code into the
target instance whenever a developer commits changes to
the source code , Hence it is referred to as CI/CD tool.
Features of Jenkins
a. Easy to Install
Jenkins is a platform-agnostic, self-contained Java-based
program, which makes it easy to run with packages for Windows,
Mac OS, and Unix-like operating systems.
b. Configuration Made Easy
Jenkins provides a web interface using which we can easily
configure it and also provides built-in help section.
c. Available Plugins
Jenkins provides hundreds of plugins which can be installed from
the Jenkins web interface for integration with other CI/CD & build
tools such as Maven, Git, Docker etc.
Plugin can installed either from the web interface or can be
downloaded from the Jenkins official website.
d. Easy Distribution

3. Jenkins can spread the workloads across multiple servers to build
applications faster, perform unit tests, and do deployments across
multiple environments and infrastructure using the master-slave
architecture.
Jenkins Architecture
Here is how Jenkins works from the Build to Deploying to
Production Environment.
1. Developers commit the code changes to the Remote
Repository such as Bitbucket , GitHub , Gitlab etc.

4. 2. Jenkins will be configured in such a way that it keeps on
checking the code changes on the remote repository at
regular intervals and pulls the newly committed code.
3. Then the Application will be generated either as a package
or as a docker image. If there is any failure during the
build process , notification will be sent to the respective
developers.
4. Jenkins will automatically deploy the latest built
application code to the testing environment. Any failures
during the deployment should be alerted to the respective
Dev and Ops team.
5. If the application is deployed successfully on the Testing
environment and verified by the respective team , Then
the code will be deployed into the Production
Environment.
Sometimes , the Jenkins server won’t be able to handle the
requests if it is hosted on a single instance.
Build process can utilize a lot of system resources
Inorder to have a successful build and deployment process , It is
better to have a Jenkins setup with Distributed architecture by
doing so load will be distributed across the agents.

5. Prerequisites
1. For this tutorial we will use the Centos server which can
either be created in On-premise and/or , it can be created
as an EC2 Instance using AWS Console or any other cloud
platform.
2. For installing Jenkins , The user must need sudo
permission or root user permission.
Installing Java
Jenkins requires java to work.
Using the below command install the java,
yum install java-11-openjdk.x86_64 -y
Check the version of Java installed in the centos system using the
below command.
java -version
Now let’s go ahead and Install Jenkins on Centos 7.

6. Installing Jenkins
Centos Operating system has the repository for Jenkins by default
, But it will not be an updated one.
To install the latest stable version of Jenkins , we have to add the
official Jenkins repository to the system
Execute the below commands to add the key and repo,
sudo wget -O
/etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-
stable/jenkins.repo
sudo rpm — import https://pkg.jenkins.io/redhat-
stable/jenkins.io.key
Install Jenkins by executing the below command.
yum install Jenkins
Jenkins service can be started using the below command.

7. sudo systemctl start Jenkins
Executing the below command , The status of Jenkins service can
be checked.
sudo systemctl status Jenkins.
To autostart the service on system bootup ,
sudo systemctl enable Jenkins
Jenkins listens on port 8080. The same can be checked by
executing the following command.
The port 8080 should be whitelisted the firewall inorder to access
the Jenkins console.
Configuring Jenkins
Access the Jenkins dashboard on the port 8080 using the below
mentioned URL

8. http://server’s IP Address:8080
You will see the following page.
Fetch the administrator password using the below command.
cat /var/lib/jenkins/secrets/initialAdminPassword
Provide the password , click Continue
Next step is to Customize Jenkins ,

9. Let us choose Install suggested plugins ,
It will take some time for the plugin to be installed.

10. After the installation of suggested plugins , We can create an
Admin user
This step can be skipped, But Let us create the user to Jenkins
instead of us in the default admin credentials.
Provide all the required details ,then click Save and Continue
Provide the root URL and then click Save and Finish.

11. Jenkins is ready to use.
Click Start using Jenkins , You will be taken to the Main Jenkins
dashboard.
Jenkins is successfully installed in the Centos operating system.
Source: https://www.zenesys.com/blog/install-and-configure-jenkins-on-centos-7