How To Install Jenkins on CentOS 7

Jenkins is an open source, Java-based automation server that offers an easy way to set up a continuous integration and continuous delivery (CI/CD) pipeline.

Continuous integration (CI) is a DevOps practice in which team members regularly commits their code changes to the version control repository, after which automated builds and tests are run. Continuous delivery (CD) is a series of practices where code changes are automatically built, tested and deployed to production.

This tutorial will walk you through the steps of installing Jenkins on a CentOS 7 system using the official Jenkins repository.

Prerequisites

Before continuing with this tutorial, make sure you are logged in as a user with sudo privileges.

Installing Jenkins

To install Jenkins on your CentOS system, follow the steps below:

1. Jenkins is a Java application, so the first step is to install Java. Run the following command to install the OpenJDK 8 package:
   ```

```console-bash
  sudo yum install java-1.8.0-openjdk-devel
  ```
  ```


  
![](http://winjay.cn/wp-content/uploads/1012-001.png)
The current version of Jenkins does not support Java 10 (and Java 11) yet. If you have multiple versions of Java installed on your machine [make sure Java 8 is the default Java version](https://linuxize.com/post/install-java-on-centos-7/#set-the-default-version).

2. The next step is to enable the Jenkins repository. To do that, import the GPG key using the following [`curl`](https://linuxize.com/post/curl-command-examples/) command: 
```

  
```console-bash
  curl --silent --location http://pkg.jenkins-ci.org/redhat-stable/jenkins.repo | sudo tee /etc/yum.repos.d/jenkins.repo
  ```
  ```


  ![](http://winjay.cn/wp-content/uploads/1012-002.png) And add the repository to your system with:

  
```

  
```console-bash
  sudo rpm --import https://jenkins-ci.org/redhat/jenkins-ci.org.key
  ```
  ```


  ![](http://winjay.cn/wp-content/uploads/1012-003.png)

  

3. Once the repository is enabled, install the latest stable version of Jenkins by typing: 
```

  
```console-bash
  sudo yum install jenkins
  ```
  ```


  ![](http://winjay.cn/wp-content/uploads/1012-004.png)

  
After the installation process is completed, start the Jenkins service with:

  
```
  
```console-bash
  sudo systemctl start jenkins
  ```
  ```


  
To check whether it started successfully run:

  
```
  
```console-bash
  systemctl status jenkins
  ```
  ```


  
You should see something similar to this:

  
```
  
```output>
  " data-lang="output>" style="box-sizing: inherit; border: 0px solid #dae1e7; font-family: Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New', monospace; font-size: 0.875rem; min-width: 0px; background-color: #f1f5f8; padding: 0px;">● jenkins.service - LSB: Jenkins Automation Server
     Loaded: loaded (/etc/rc.d/init.d/jenkins; bad; vendor preset: disabled)
     Active: active (running) since Fri 2018-11-02 13:37:46 CST; 34s ago
       Docs: man:systemd-sysv-generator(8)
     CGroup: /system.slice/jenkins.service
             └─12688 /etc/alternatives/java -Dcom.sun.akuma.Daemon=daemonized -Djava.awt.headless=true -DJENKINS_HOME=/var/lib/jenkins -jar /usr/lib/jenkins/jenkins.war --.● jenkins.service - LSB: Jenkins Automation Server

  

  ```Finally enable the Jenkins service to start on system boot.

  ```

  
```

  
```console-bash
  sudo systemctl enable jenkins
  ```
  ```


  
```

  
```output
  jenkins.service is not a native service, redirecting to /sbin/chkconfig.
  Executing /sbin/chkconfig jenkins on
  ```
  ```


  ![](http://winjay.cn/wp-content/uploads/1012-005.png)

  

[Adjust the Firewall](https://linuxize.com/post/how-to-install-jenkins-on-centos-7/#adjust-the-firewall)
--------------------------------------------------------------------------------------------------------

If you are installing Jenkins on a remote CentOS server that is [protected by a firewall](https://linuxize.com/post/how-to-setup-a-firewall-with-firewalld-on-centos-7/) you need to port `8080`.

Use the following commands to open the necessary port:

```
```console-bash
sudo firewall-cmd --permanent --zone=public --add-port=8080/tcp
sudo firewall-cmd --reload
```
```


![](http://winjay.cn/wp-content/uploads/1012-006.png)

[Setting Up Jenkins](https://linuxize.com/post/how-to-install-jenkins-on-centos-7/#setting-up-jenkins)
------------------------------------------------------------------------------------------------------

To setup your new Jenkins installation, open your browser and type your domain or IP address followed by port `8080`:

```
```url
http://your_ip_or_domain:8080
```
```


A screen similar to the following will appear, prompting you to enter the Administrator password that is created during the installation:

![](http://winjay.cn/wp-content/uploads/1012-007.png)
Use the following command to print the password on your terminal:

```
[root@Jenkins ~]# cat /var/lib/jenkins/secrets/initialAdminPassword 
4665d7d605744391a1712026cc3e636e
```


Copy the password from your terminal, paste it into the Administrator password field and click `Continue`.

![](https://linuxize.com/post/how-to-install-jenkins-on-centos-7/customize-jenkins.jpg)
On the next screen you will be asked whether you want to install the suggested plugins or to select specific plugins. Click on the `Install suggested plugins` box, and the installation process will start immediately.

![](https://linuxize.com/post/how-to-install-jenkins-on-centos-7/jenkins-getting-started.jpg)
Once the installation is complete, you will be prompted to set up the first administrative user. Fill out all required information and click `Save and Continue`.

![](http://winjay.cn/wp-content/uploads/1012-010.png)
On the next page you will be asked to set the URL for the Jenkins instance. The URL filed will be populated with an automatically generated URL.

![](http://winjay.cn/wp-content/uploads/1012-011.png)
To complete the setup confirm the URL by clicking on the `Save and Finish` button.

![](http://winjay.cn/wp-content/uploads/1012-012.png)
Finally, click on the `Start using Jenkins` button and you will be redirected to the Jenkins dashboard logged in as the admin user you have created in one of the previous steps.

![](http://winjay.cn/wp-content/uploads/1012-013.png)
![](http://winjay.cn/wp-content/uploads/1012-014.png)
If you’ve reached this point, you’ve successfully installed Jenkins on your CentOS system.

[Conclusion](https://linuxize.com/post/how-to-install-jenkins-on-centos-7/#conclusion)
--------------------------------------------------------------------------------------

In this tutorial, you have learned how to install and complete the initial configuration of Jenkins on CentOS/RHEL based systems. You can now visit the official [Jenkins documentation](https://jenkins.io/doc/) page and start exploring Jenkins’s workflow and plug-in model.

If you have any question, please leave a comment below.