Jenkins Docker Image

This repository contains Dockerfiles for a Jenkins Docker image intended for use with OpenShift v3

For an example of how to use it, see this sample.

The image is pushed to DockerHub as openshift/jenkins-1-centos7.

For more information about using these images with OpenShift, please see the official OpenShift Documentation.

Versions

Jenkins versions currently provided are:

• jenkins-1.6x

RHEL versions currently supported are:

• RHEL7

CentOS versions currently supported are:

• CentOS7

Installation

Choose either the CentOS7 or RHEL7 based image:

• RHEL7 based image

  To build a RHEL7 based image, you need to run Docker build on a properly subscribed RHEL machine.

  $ git clone https://github.com/openshift/jenkins.git
  $ cd jenkins
  $ make build TARGET=rhel7 VERSION=1
  

• CentOS7 based image

  This image is available on DockerHub. To download it run:

  $ docker pull openshift/jenkins-1-centos7
  

  To build a Jenkins image from scratch run:

  $ git clone https://github.com/openshift/jenkins.git
  $ cd jenkins
  $ make build VERSION=1
  

Notice: By omitting the VERSION parameter, the build/test action will be performed on all provided versions of Jenkins. Since we are currently providing only version 1, you can omit this parameter.

Environment variables

The image recognizes the following environment variables that you can set during initialization by passing -e VAR=VALUE to the Docker run command.

Variable name	Description
JENKINS_PASSWORD	Password for the 'admin' account

You can also set the following mount points by passing the -v /host:/container flag to Docker.

Volume mount point	Description
/var/lib/jenkins	Jenkins config directory

Notice: When mounting a directory from the host into the container, ensure that the mounted directory has the appropriate permissions and that the owner and group of the directory matches the user UID or name which is running inside the container.

Plugins

Installing using layering

In order to install additional Jenkins plugins, the OpenShift Jenkins image provides a way how to add those by layering on top of this image. The derived image, will provide the same functionality as described in this documentation, in addition it will also include all plugins you list in the plugins.txt file.

To create derived image, you have to write following Dockerfile:

FROM openshift/jenkins-1-centos7
COPY plugins.txt /opt/openshift/configuration/plugins.txt
RUN /usr/local/bin/plugins.sh /opt/openshift/configuration/plugins.txt

The format of plugins.txt file is:

pluginId:pluginVersion

For example, to install the github Jenkins plugin, you specify following to plugins.txt:

github:1.11.3

After this, just run docker build -t my_jenkins_image -f Dockerfile.

Installing using S2I build

The s2i tool allows you to do additional modifications of this Jenkins image. For example, you can use S2I to copy custom Jenkins Jobs definitions, additional plugins or replace the default config.xml file with your own configuration.

To do that, you can either use the standalone s2i tool, that will produce the customized Docker image or you can use OpenShift Source build strategy.

In order to include your modifications in Jenkins image, you need to have a Git repository with following directory structure:

• ./plugins folder that contains binary Jenkins plugins you want to copy into Jenkins
• ./plugins.txt file that list the plugins you want to install (see the section above)
• ./configuration/jobs folder that contains the Jenkins job definitions
• ./configuration/config.xml file that contains your custom Jenkins configuration

Note that the ./configuration folder will be copied into /var/lib/jenkins folder, so you can also include additional files (like credentials.xml, etc.).

To build your customized Jenkins image, you can then execute following command:

$ s2i build https://github.com/your/repository openshift/jenkins-1-centos7 your_image_name

Included plugins

• OpenShift Pipeline Plugin

See the following, as well an example use of the plugin's capabilities with the OpenShift Sample Job included in this image. For more details visit the Jenkins plugin website.

• Kubernetes Plugin This plugin allows slaves to be dynamically provisioned on multiple Docker hosts using Kubernetes. To learn how to use this plugin, see the example available in the OpenShift Origin repository. For more details about plugin, visit the plugin web site.

Usage

For this, we will assume that you are using the openshift/jenkins-1-centos7 image. If you want to set only the mandatory environment variables and store the database in the /tmp/jenkins directory on the host filesystem, execute the following command:

$ docker run -d -e JENKINS_PASSWORD=<password> -v /tmp/jenkins:/var/lib/jenkins openshift/jenkins-1-centos7

Jenkins admin user

The admin user name is set to admin and you have to to specify the password by setting the JENKINS_PASSWORD environment variable. This process is done upon initialization.

Test

This repository also provides a test framework which checks basic functionality of the Jenkins image.

Users can choose between testing Jenkins based on a RHEL or CentOS image.

• RHEL based image

  To test a RHEL7 based Jenkins image, you need to run the test on a properly subscribed RHEL machine.

  $ cd jenkins
  $ make test TARGET=rhel7 VERSION=5.5
  

• CentOS based image

  $ cd jenkins
  $ make test VERSION=1
  

Notice: By omitting the VERSION parameter, the build/test action will be performed on all provided versions of Jenkins. Since we are currently providing only version 1, you can omit this parameter.