How to install Jenkins on Ubuntu 24.04

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If you’re exploring continuous integration and deployment, Jenkins is a powerful tool that simplifies automation tasks. In this guide, we’ll walk you through installing Jenkins on an Ubuntu 24.04 EC2 instance. Whether you’re new to Jenkins or looking for an easy setup, this tutorial is tailored to you.

Prerequisites

Before we begin, make sure you have the following:

AWS Account: You’ll need an active AWS account to launch an EC2 instance. Sign up here.
Basic Knowledge of Linux: Familiarity with terminal commands will help.
EC2 Instance: An Ubuntu 24.04 instance running with a security group allowing port 8080. You can follow this beginner’s guide to create an Ubuntu machine.

Step 1: Update Your System

Once connected to your EC2 instance, updating your system is crucial. This ensures that all installed packages are the latest versions, minimizing compatibility and security issues.

Run the following command to update:

sudo apt update

This command performs:

apt update: This command fetches the latest package lists from the configured repositories. It updates your local metadata about available packages, including new versions and dependencies, but does not install or upgrade any packages.

apt upgrade -y: you can try this command after above step, this command upgrades all installed packages to their latest available versions based on the current package lists (retrieved by apt update). It installs the updated versions while keeping the existing packages and their configurations.

Step 2: Install Java

Jenkins is a Java-based application, and it requires Java to run. As per the official Jenkins installation guide, we will use Java 17.

To install Java, run the following command:

sudo apt install fontconfig openjdk-17-jre

After the successful installation, you will see a response like the above image, To confirm the installation, check the Java version:

java -version

Expected output:

It should display openjdk version "17.0.8" confirming the installation.

Java acts as the runtime environment for Jenkins, enabling it to execute.

Step 3: Add Jenkins Repository

To install Jenkins, we need to add its official repository to our system. This ensures that we’re installing the latest stable version. copy the below command and paste it into your terminal.

sudo wget -O /usr/share/keyrings/jenkins-keyring.asc \
https://pkg.jenkins.io/debian/jenkins.io-2023.key
echo "deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc]" \
https://pkg.jenkins.io/debian binary/ | sudo tee \
/etc/apt/sources.list.d/jenkins.list > /dev/null
sudo get update

Explanation

Add the Jenkins key: sudo wget -O /usr/share/keyrings/jenkins-keyring.asc \ https://pkg.jenkins.io/debian/jenkins.io-2023.key This command downloads the Jenkins signing key and stores it securely.
Add the Jenkins repository to your package manager: echo "deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc]" \ https://pkg.jenkins.io/debian binary/ | sudo tee \ /etc/apt/sources.list.d/jenkins.list > /dev/null This command adds Jenkins to the list of sources your system will check for software updates.
Update your package list to include Jenkins: sudo apt update Now your system is aware of the Jenkins package and ready for installation.

Step 4: Install Jenkins

Install Jenkins with the following command:

sudo apt-get install jenkins

Here’s what happens:

Downloads Jenkins from the added repository.
Installs all required dependencies.

After installation, start the Jenkins service:

sudo systemctl start jenkins

Enable Jenkins to start on boot:

sudo systemctl enable jenkins

Check if Jenkins is running:

sudo systemctl status jenkins

If it’s successful, you’ll see a message indicating Jenkins is active and running. like the image shown above

Step 5: Configure Firewall Rules

By default, Jenkins listens on port 8080. To access Jenkins from a browser, ensure the firewall allows traffic on this port.

For Ubuntu’s UFW:

Enable UFW if it’s not already active: sudo ufw enable
Allow OpenSSH and Jenkins traffic: sudo ufw allow OpenSSH sudo ufw allow 8080
Verify the rules: sudo ufw status

This configuration ensures Jenkins is accessible while keeping other ports secure.

Step 6: Update Security Group Rules

Before accessing Jenkins, ensure that the security group (SG) associated with your EC2 instance has an inbound rule allowing traffic on port 8080. This is necessary to access the Jenkins web interface from your browser.

Select your EC2 instance to view its details.
Under the “Security” tab, click on the “Security Groups” linked to your instance.
In the Security Group settings, go to the “Inbound rules” section and click “Edit inbound rules”.

Add a new rule with the following details:
- Type: Custom TCP Rule
- Protocol: TCP
- Port Range: 8080
- Source: Anywhere (0.0.0.0/0) or restrict it to your IP for better security.
Click “Save rules” to apply the changes.

Step 7: Access Jenkins Web Interface

Now that Jenkins is installed and the firewall is configured, it’s time to access it via a web browser:

Open your browser and navigate to: http://<your-ec2-public-ip>:8080 Replace <your-ec2-public-ip> with the public IP of your EC2 instance.

You’ll see an “Unlock Jenkins” page. To retrieve the initial admin password: sudo cat /var/lib/jenkins/secrets/initialAdminPassword Copy the password displayed in the terminal.

Paste the password into the web interface and click Continue.

Install recommended plugins when prompted.

Create an admin user to complete the setup.

Jenkins is now ready for use.

Step 8: Secure Your Jenkins Instance

For production environments, securing Jenkins is essential. Here’s how:

Use HTTPS: Configure SSL for encrypted communication. Let’s Encrypt is a free and reliable option.
Restrict Access: Update your EC2 security group to allow access only from trusted IPs.
Keep Jenkins Updated: Regular updates ensure security patches and new features.

Additional Resources

Conclusion

Setting up Jenkins on an Ubuntu 24.04 EC2 instance is a straightforward process. With Jenkins, you can automate your CI/CD and improve development efficiency. Follow this guide step-by-step, and you’ll have Jenkins running quickly.

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