agileek/docker-jenkins repository overview

⁠Official Jenkins Docker image

The Jenkins Continuous Integration and Delivery server.

This is a fully functional Jenkins server, based on the Latest version http://jenkins-ci.org/⁠

⁠Usage

docker run -p 8080:8080 jenkins

This will store the workspace in /var/jenkins_home. All Jenkins data lives in there - including plugins and configuration. You will probably want to make that a persistent volume (recommended):

docker run -p 8080:8080 -v /your/home:/var/jenkins_home jenkins

This will store the jenkins data in /your/home on the host. Ensure that /your/home is accessible by the jenkins user in container (jenkins user - uid 102 normally - or use -u root).

You can also use a volume container:

docker run --name myjenkins -p 8080:8080 -v /var/jenkins_home jenkins

Then myjenkins container has the volume (please do read about docker volume handling to find out more).

⁠Backing up data

If you bind mount in a volume - you can simply back up that directory (which is jenkins_home) at any time.

This is highly recommended. Treat the jenkins_home directory as you would a database - in Docker you would generally put a database on a volume.

If your volume is inside a container - you can use docker cp $ID:/var/jenkins_home command to extract the data. Note that some symlinks on some OSes may be converted to copies (this can confuse jenkins with lastStableBuild links etc)

⁠Attaching build executors

You can run builds on the master (out of the box) buf if you want to attach build slave servers: make sure you map the port: -p 50000:50000 - which will be used when you connect a slave agent.

Here⁠ is an example docker container you can use as a build server with lots of good tools installed - which is well worth trying.

⁠Passing JVM parameters

You might need to customize the JVM running Jenkins, typically to pass system properties or tweak heap memory settings. Use JAVA_OPTS environment variable for this purpose :

docker run --name myjenkins -p 8080:8080 -env JAVA_OPTS=-Dhudson.footerURL=http://mycompany.com jenkins

⁠Passing Jenkins launcher parameters

Argument you pass to docker running the jenkins image are passed to jenkins launcher, so you can run for sample :

docker run jenkins --version

This will dump Jenkins version, just like when you run jenkins as an executable war.

You also can define jenkins arguments as JENKINS_OPTS. This is usefull to define a set of arguments to pass to jenkins launcher as you define a derived jenkins image based on the official one with some customized settings. The following sample Dockerfile uses this option to force use of HTTPS with a certificate included in the image

FROM jenkins:1.565.3

COPY https.pem /var/lib/jenkins/cert
COPY https.key /var/lib/jenkins/pk
ENV JENKINS_OPTS --httpPort=-1 --httpsPort=8083 --httpsCertificate=/var/lib/jenkins/cert --httpsPrivateKey=/var/lib/jenkins/pk
EXPOSE 8083

⁠Installing more tools

You can run your container as root - and unstall via apt-get, install as part of build steps via jenkins tool installers, or you can create your own Dockerfile to customise, for example:

FROM jenkins
USER root # if we want to install via apt
RUN apt-get install -y ruby make more-thing-here
USER jenkins # drop back to the regular jenkins user - good practice

In such a derived image, you can customize your jenkins instance with hook scripts or additional plugins. Those need to be packaged inside the executed jenkins.war, so use :

RUM mkdir /tmp/WEB-INF/plugins
RUN curl -L https://updates.jenkins-ci.org/latest/git.hpi -o /tmp/WEB-INF/plugins/git.hpi
RUN curl -L https://updates.jenkins-ci.org/latest/git-client.hpi -o /tmp/WEB-INF/plugins/git-client.hpi
RUN cd /tmp; zip --grow /usr/share/jenkins/jenkins.war WEB-INF/* 

Also see JENKINS-24986⁠

⁠Upgrading

All the data needed is in the /var/jenkins_home directory - so depending on how you manage that - depends on how you upgrade. Generally - you can copy it out - and then "docker pull" the image again - and you will have the latest LTS - you can then start up with -v pointing to that data (/var/jenkins_home) and everything will be as you left it.

As always - please ensure that you know how to drive docker - especially volume handling!

⁠Questions?

Jump on irc.freenode.net and the #jenkins room. Ask!