Docker Image Builder & Run Utilities for Jenkins

Ryan Price, ryapric@gmail.com

This repository serves as a set of tools to deploy a Jenkins CI instance with just a few short commands. The Jenkins master is deployed as a Docker container, and is designed to run its jobs using Docker, as well! This works by binding the host's Docker socket and binary path, to the Jenkins container, which makes the host installation of Docker available to Jenkins without a redundant second installation.

All of the work done to configure Jenkins jobs, users, credentials, etc. are all stored persistently, even if the container is stopped, via mounting a Docker volume named "jenkins_home". So, just because your container goes down, doesn't mean you ever have to re-do the initial set-up described in this README.

Prerequisites

1. A browser to access to the host machine's IP address (if local, then localhost; if deploying to the cloud, then use your best judgement on how to proceed)

2. Docker

3. A machine with a supported (x86-64) OS installed:

   • Debian
   • Ubuntu
   • Fedora
   • CentOS
   • Raspbian (though you'll need to know the right Docker images to use for ARM architectures; not supported in this repo's default config)

4. 20 extra minutes for a one-time manual set-up of Jenkins administrative tools (users, plugins, etc).

How To Deploy

!!! Reminder to always review every bit of code that you get from the internet !!!

Actual deployment of the Jenkins container is very easy, even if Docker isn't yet installed. The full step-by-step instructions, from "I have nothing" to running the Jenkins container, are as follows:

1. Clone this repo, and cd inside:

   • git clone https://github.com/ryapric/jenkins_docker.git && cd jenkins_docker

2. Install Docker. Recent means of Docker installation is quite easy, via their official install script, which can be run via:

   • curl -sSL https://get.docker.com | sh

3. Build a modified Jenkins image using the included Dockerfile. This is unfortunately necessary because to use Docker build agents, inside of Docker, at least one other deb package needs to be installed (libltdl-dev). You can build an image via (feel free to change the image name):

   • docker build -t jenkins_docker .

4. Run docker-run.sh, with the name of the new Jenkins image as the sole argument. This script starts an instance of the Jenkins image you just built, mounts the jenkins_home Docker volume, binds ports 8080 and 50000, and gives the container access to the host Docker socket. The container is deployed with the friendly name "jenkins", which is printed to stdout as a reminder once the script completes successfully. If you re-run this script for any reason after the initial run, it will automatically shut down any running containers with the name "jenkins".

   • sh docker-run.sh jenkins_docker

5. Browse to <machine-ip-address>:8080, and paste the password that is output from the following command. This allows you to perform the initial configuration for the Jenkins master (you only need to do this & the next step once, as all configs are stored in the Docker volume)

   • docker container exec jenkins cat /var/jenkins_home/secrets/initialAdminPassword

6. Follow the prompts to continue configuring Jenkins. They should be: install plugins, add an Admin user, and then "Start Using Jenkins". Once you're set up, you can install additional plugins (again, all persistent) via "Configure Jenkins --> Manage Plugins".

That's it! Five commands and some UI prompts, and you're all set to start configuring your builds & jobs!

If you want to make some docker-run changes, just save them and re-run the script. As stated above, it should handle the container restart for you pretty elegantly.

If you have read & understood the above steps, and are comfortable with them, you can also just use the one-step deployment script in this repo, full_deploy_from_scratch.sh. It is important to understand all of the above, however, since restarting the container, rebuilding the image, etc. as needed have their own scripts.

Other Things You Can Do!

Feel free, of course, to fork this repository at any time, and use it as boilerplate to VC your own desired Jenkins configurations. Some ideas:

• Modify the Dockerfile to build a Jenkins image that has more programs pre-installed when the container runs (good if you don't want Docker to be the build agent inside the Jenkins container)

• Modify the docker-run script to mount more volumes, change port bindings, edit other runtime configs, etc.

• Etc.

License

GPL-3