Build Jenkins master Docker image with preinstalled plugins

Key takeaways:

• Create a Dockerfile to set up Jenkins with preinstalled plugins.

• Use a plugins.txt file to specify desired plugins and versions.

• Build the Docker image with docker build -t <image_name> . command.

• Run the Jenkins container with mapped ports and persistent storage using Docker volume.

• Access Jenkins at http://localhost:8080 to verify plugins are preinstalled.

• Setting JAVA_OPTS=-Djenkins.install.runSetupWizard=false skips the Jenkins setup wizard, saving setup time.

To build a Jenkins master Docker image with preinstalled plugins, follow these steps. This involves creating a Dockerfile that installs Jenkins, the required plugins, and configures the environment for smooth operation.

Prerequisites

You’ll have to install Docker on your machine if you want to follow along locally.

Steps to create a Jenkins Docker image with preinstalled plugins

The following are the steps to create a Jenkins master Docker image with preinstalled plugins:

1. Install Docker

Ensure that Docker is installed on your system. Follow the code below:

2. Create a Dockerfile

Create a Dockerfile that installs Jenkins, Jenkins plugins, and any other dependencies. Below is a sample Dockerfile:

• Line 1: To build the Jenkins Master image, we’ll include the Jenkins base image in our Dockerfile.

• Line 3: We use downloaded .hpi files and copy them to /usr/share/jenkins/ref/plugins/ within the Dockerfile.

• Line 4: We specify plugins to download via a plugins.txt file.

• Line 5: Plugins can be manually installed by specifying them in the jenkins-plugin-cli command.

3. Create a plugins.txt file

This file lists all the Jenkins plugins you want to preinstall. Here’s an example of plugins.txt:

You can customize this list by adding or removing plugins based on your needs. Make sure the plugin versions you specify are compatible with the version of Jenkins you’re using.

4. Build the Docker image

Now that your Dockerfile and plugins.txt are ready, you can build your Docker image. Run the following command in the directory where your Dockerfile is located:

5. Run the Jenkins container

Once the Docker image is built, you can run it as a container using the following command:

• -d: Runs the container in detached mode.

• -p 8080:8080: Maps the container’s port 8080 to the host’s port 8080 (for the Jenkins web interface).

• -p 50000:50000: Maps the container’s port 50000 to the host’s port 50000 (for Jenkins agents).

• -v jenkins_home:/var/jenkins_home: Creates a volume for persistent storage of Jenkins data.

6. Access Jenkins

Open your browser and go to http://localhost:8080. Jenkins will start with the plugins you preinstalled.

Try it out!

Apply what you have learned by using the provided terminal. You’re provided with the necessary files.

Note: The Dockerfile also includes the ENV JAVA_OPTS=-Djenkins.install.runSetupWizard=false statement to skip the installation wizard.

Press the “Run” button, build the image, and run the Jenkins container using the commands below. Then click the link in the widget below to see Jenkins with the plugins you preinstalled.

Conclusion

In conclusion, building a Jenkins master Docker image with preinstalled plugins streamlines the setup and ensures that Jenkins is configured and ready for immediate use with all necessary plugins. By following the steps outlined—creating a Dockerfile, specifying plugins in a plugins.txt file, building the Docker image, and running the container—you can automate the Jenkins setup process and improve consistency across environments. This approach is ideal for maintaining a reproducible Jenkins setup, making it easier to manage plugin dependencies and configurations, which ultimately enhances efficiency in CI/CD workflows.