Jenkins Servers Fully Loaded
….with your build configuration and build pipeline
Our use case was to create a build pipeline for our Jenkins docker image that we would be deploying to different departments. The obvious choice was to use Jenkins for Jenkins(j4j).
Setting up a build pipeline is easy with Jenkins, but in the true form of build as code, infrastructure as code and our environments being as disposable as possible, I recently tried to get a full running and configured docker image running Jenkins and with build jobs and pipelines ready to be run as soon as the image was deployed.
Turns out it was really easy but I struggled to find clear, concise steps on how to do this so though I would quickly put this article together.
If you have ever installed Jenkins or used the Jenkins docker image, you would have noticed, that you need to view log files to provide the initial password, go through set up screens to install plugins and configure. Using our Dockerfile, you will see how easy it is in the next few lines that we were able to:
- Define environment variables
- Install plugins needed
- Run through the Jenkins default setup page
- Setup default users and configurations
- Set up and configure a sample build
Building the Jenkins Dockerfile
Lets try to keep things as simple and streamlined so for now we are going to use the provided Jenkins image on docker hub. You can find the entire code at the following github repo, but for now we will add the lines for each section:
Installing all the plugins you need
If you are using a lightweight docker version of Jenkins, you may need to install install-plugins.sh script an supporting modules into your image before you can get this running, but by using this you can simply list all of the Jenkins plugins you need just like you would using yum or apt.
# Install plugins
RUN /usr/local/bin/install-plugins.sh build-pipeline-plugin docker-plugin git ssh-credentials workflow-aggregator scm-api git-client greenballs docker-build-publish amazon-ecr docker-workflow
Defining Jenkins user and password
Pretty easy using the ENV option in our Dockerfile:
ENV JENKINS_USER admin
ENV JENKINS_PASS admin
Skipping the initial setup and setting up default users
By setting up another environment variable for the Jenkins application to run from we can bypass the initial setup. The -Djenkins.install.runSetupWizard can be set to false to stop this from running. We can also move our executors and default-users groovy scripts into the /usr/share/jenkins/ref/init.groovy.d/ directory to be used when our docker image is implemented
# Skip initial setup
ENV JAVA_OPTS -Djenkins.install.runSetupWizard=false
COPY executors.groovy /usr/share/jenkins/ref/init.groovy.d/
COPY default-user.groovy /usr/share/jenkins/ref/init.groovy.d/
Adding in builds, configuration and other details
The great thing about the ref directory under /usr/share/jenkins/ is that everything in place in the ref directory will be implemented in the Jenkins home directory when the image is launched. This means that any server configurations, build jobs and even build history can be placed into the ref directory and will be in place and ready to role when we start things up.
# Add Build Jobs And Configurations
ADD ref /usr/share/jenkins/ref/
This is something that Jenkins has put together to make things run a little smoother and allow you to define your build as code. It sit’s nicely in the root of your application repository and defines the build steps for your application in nice groovy format. I won’t go into this in depth as it’s probably best for another time, but at the download you will be able to find a sample.
Install Supporting Applications
Once again, pretty simple where we change into the root user and install all of the supporting applications that we will need to have running in our Jenkins environment.
RUN apt-get update && apt-get install -y rsync sudo python-setuptools python-dev build-essential && easy_install pip && pip install awscli && rm -rf /var/lib/apt/lists/*
Allow the jenkins user to play as sudo
Not everyone will need this, but there are some circumstances where might want this
RUN echo “jenkins ALL=NOPASSWD: ALL” >> /etc/sudoers
Building the Image:
docker build -t jenkins-test .
docker run -d -p 8080:8080 jenkins-test
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About The Author
Vince has worked with Splunk for over 5 years, developing apps and reporting applications around Splunk, and now works hard to advocate its success. He has worked as a system engineer in big data companies and development departments, where he has regularly supported, built, and developed with Splunk. He has now published his first book via Packt Publishing — Learning Splunk Web Framework.