Chapter 2 – Installing Jenkins

Prerequisites

Software: Java 8 (JRE or JDK). Install with yum -y install java .

Hardware: Minimum 256 MB RAM and 1 GB disk (Docker recommends 10 GB). Small teams should have 1 GB+ RAM and 50 GB+ disk.

Note: When running Jenkins in Docker, these resources are not required.

Installation Options

WAR package deployment : Place the downloaded jenkins.war in a chosen directory and start with java -jar jenkins.war . Access via http://localhost:8080 (port can be changed with --httpPort=9090 ).

macOS (Homebrew): brew install jenkins for the latest version or brew install jenkins-lts for the LTS release.

Windows : Download the installer and follow the wizard.

Linux (recommended) :

Download the RPM package.

Install with rpm –ivh jenkins-2.150.3-1.1.noarch.rpm .

Start the service: service jenkins start .

Enable on boot: chkconfig jenkins on .

Post‑Installation Configuration

Unlock Jenkins : Retrieve the initial admin password from $JENKINS_HOME/secrets/initialAdminPassword or the startup log.

Install plugins : Choose suggested plugins or select custom ones; additional plugins can be installed later via the plugin manager.

Create admin user : Set up an administrator account to complete the initial setup.

Configure update site : Use a faster mirror, e.g., https://mirrors.tuna.tsinghua.edu.cn/jenkins/updates/update-center.json .

Configure slave node :

Navigate to Manage Jenkins → Manage Nodes and create a new node.

Download agent.jar and start it with the generated command, for example:

wget http://192.168.0.41/jnlpJars/agent.jar<br/>java -jar agent.jar -jnlpUrl http://192.168.0.41/computer/test1/slave-agent.jnlp -secret 807b0135fb5b071d99930166ac4fc5dd0cf355e670a66da73120dfa2e8cebc5f -workDir "/var/lib/jenkins"

Verify that the slave starts successfully.

Jenkins configuration file : For RPM installations, the config file is located at /etc/sysconfig/jenkins , where startup parameters and ports can be defined.