Install Jenkins in Rocky Linux 9

Install Jenkins on Rocky Linux:

1. Update:

   sudo dnf update -y

2. Install Java: Jenkins requires Java to run. Install OpenJDK 11, which is a recommended version for Jenkins:

   sudo dnf install -y java-11-openjdk-devel

(optional) sudo dnf install java-1.8.0-openjdk wget gnupg

3. Add the Jenkins repository: Create a new repo file for Jenkins in /etc/yum.repos.d/:

   sudo tee /etc/yum.repos.d/jenkins.repo <<EOF
   

[jenkins]
name=Jenkins
baseurl=http://pkg.jenkins.io/redhat-stable/
enabled=1
gpgcheck=1
gpgkey=https://pkg.jenkins.io/redhat-stable/jenkins.io.key

4. Import the Jenkins GPG key:

   sudo rpm --import https://pkg.jenkins.io/redhat/jenkins.io.key

5. Install Jenkins:

   sudo dnf install -y jenkins

6. Start and enable Jenkins service:

   sudo systemctl start jenkins
   sudo systemctl enable jenkins

7. Open the necessary firewall ports: Jenkins by default runs on port 8080. To allow traffic through this port, run:

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

8. Access Jenkins: Open web browser and navigate to http://localhost:8080, should see the Jenkins setup wizard.
9. Retrieve the initial admin password: To complete the setup wizard, will need the initial admin password. Can retrieve it using the following command:

sudo su -
cd /var/lib/jenkins/secrets/
cat /var/lib/jenkins/secrets/initialAdminPassword | xclip -selection clipboard

Use this password to unlock Jenkins and complete the initial setup.