kryndex / jenkins-3

Jenkins Docker Image

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

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

The images are pushed to DockerHub as openshift/jenkins-2-centos7, openshift/jenkins-slave-base-centos7, openshift/jenkins-slave-maven-centos7, and openshift/jenkins-slave-nodejs-centos7.

Development of the V1 Jenkins images has ceased.

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

Versions

Jenkins versions currently provided are:

• jenkins-1.6x - DEPRECATED
• jenkins-2.x

RHEL versions currently supported are:

• RHEL7

CentOS versions currently supported are:

• CentOS7

Installation

Choose either the CentOS7 or RHEL7 based image:

• RHEL7 based image

  You can access these images from the Red Hat Container Catalog. See:

  • https://access.redhat.com/containers/#/registry.access.redhat.com/openshift3/jenkins-2-rhel7
  • https://access.redhat.com/containers/#/registry.access.redhat.com/openshift3/jenkins-slave-base-rhel7
  • https://access.redhat.com/containers/#/registry.access.redhat.com/openshift3/jenkins-slave-maven-rhel7
  • https://access.redhat.com/containers/#/registry.access.redhat.com/openshift3/jenkins-slave-nodejs-rhel7

  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=2
  

• CentOS7 based image

  The images are available on DockerHub. An example download command is:

  $ docker pull openshift/jenkins-2-centos7
  

  To build a Jenkins image from scratch run:

  $ git clone https://github.com/openshift/jenkins.git
  $ cd jenkins
  $ make build VERSION=2
  

Notice: By omitting the VERSION parameter, the build/test action will be performed on all provided versions of Jenkins.

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 when using default Jenkin authentication.
OPENSHIFT_ENABLE_OAUTH	Determines whether the OpenShift Login plugin manages authentication when logging into Jenkins.
OPENSHIFT_PERMISSIONS_POLL_INTERVAL	Specifies in milliseconds how often the OpenShift Login plugin polls OpenShift for the permissions associated with each user defined in Jenkins.
INSTALL_PLUGINS	Comma-separated list of additional plugins to install on startup. The format of each plugin spec is plugin-id:version (as in plugins.txt)
OVERRIDE_PV_CONFIG_WITH_IMAGE_CONFIG	When running this image with an OpenShift persistent volume for the Jenkins config directory, the transfer of configuration from the image to the persistent volume is only done the first startup of the image as the persistent volume is assigned by the persistent volume claim creation. If you create a custom image that extends this image and updates configuration in the custom image after the initial startup, by default it will not be copied over, unless you set this environment variable to some non-empty value.
OVERRIDE_PV_PLUGINS_WITH_IMAGE_PLUGINS	When running this image with an OpenShift persistent volume for the Jenkins config directory, the transfer of plugins from the image to the persistent volume is only done the first startup of the image as the persistent volume is assigned by the persistent volume claim creation. If you create a custom image that extends this image and updates plugins in the custom image after the initial startup, by default they will not be copied over, unless you set this environment variable to some non-empty value.

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

Base set of plugins

An initial set of Jenkins plugins are included in the OpenShift Jenkins images. The general methodology is that the CentOS7 image if first updated with any changes to the list of plugins. After some level of verification with that image, the RHEL7 image is updated.

Plugin installation for CentOS7

The top level list of plugins to install is located here. The format of the file is:

pluginId:pluginVersion

The file is processed by the following call in the CentOS7 Dockerfile:

/usr/local/bin/install-plugins.sh /opt/openshift/base-plugins.txt

Where both base-plugins.txt and install-plugins.sh are copied into the image prior to that invocation.

The running of install-plugins.sh will download the files listed in base-plugins.txt, and then open each plugin's manifest and download any needed dependencies listed, including upgrading any previously installed dependencies as needed.

To update the version of a plugin or add a new plugin, construct a PR for this repository that updates base-plugins.txt appropriately. Administrators for this repository will make sure necessary tests are run and merge the PR when things are ready.

When PRs for this repository are merged, they kick off associated builds in the push_jenkins_images job on OpenShift's public Jenkins CI/CD server. When those builds complete, new versions of the CentOS7 based versions of the images produced by this repository are pushed to Docker Hub. See the top of the README for the precise list.

Plugin installation for RHEL7

Only OpenShift developers working for Red Hat can update the list of plugins for the RHEL7 image. For those developers, visit this internal Jenkins server and log in (contact our CD team for permissions to this job). Click the Build with parameters link, update the PLUGIN_LIST field, and submit the build. The format of the data for the PLUGIN_LIST field is the same as base-plugins.txt.

The complete list of plugins (i.e. including dependencies) needs to be provided though. The most straight forward approach is to mine the output of the CentOS7 build which passed verification for the complete list. Just search for Installed plugins: and leverage copy/paste to compile what is needed.

Although this document will refrain on detailing the precise details, once the build on the internal Jenkins server is complete, the processes will be set in motion to build the jenkins-2-plugins RPM that is installed by the RHEL7 Dockerfile when the next version of the RHEL7 based OpenShift Jenkins image is built. When new versions of OpenShift are released, associated versions of the RHEL7 based versions of the images produced by this repository are pushed to the Docker registry provided to RHEL7 subscribers.

Some reference links for the OpenShift Jenkins developers and where things cross over with the CD/CL/Atomic/RHEL teams:

• http://pkgs.devel.redhat.com/cgit/rpms/?q=jenkins
• https://brewweb.engineering.redhat.com/brew/search?match=glob&type=package&terms=*jenkins*

Adding plugins or updating existing plugins

A combination of the contents of this repository and the capabilities of OpenShift allow for a variety of ways to modify the list of plugins either for the images directly produced from this repository, or by creating images which build from the images directly produced from this repository.

The specifics for each approach are detailed below.

Installing using layering

In order to install additional Jenkins plugins, the OpenShift Jenkins image provides a way similar to how the initial set of plugins are added to this image that will allow one to add or update 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 a derived image in this fashion, create the following Dockerfile:

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

NOTE: if instead of adding a plugin you want to replace an existing plugin via dropping the binary plugin in the ./plugins directory, make sure the filename ends in .jpi.

Installing on Startup

The INSTALL_PLUGINS environment variable may be used to install a set of plugins on startup. When using a persistent volume for /var/lib/jenkins, plugin installation will only happen on the initial run of the image.

In the following example, the Groovy and Pull Request Builder plugins are installed

INSTALL_PLUGINS=groovy:1.30,ghprb:1.35.0

Plugins focused on integration with OpenShift

A subset of the plugins included by the images of this repository play a direct part in integrating between Jenkins and OpenShift.

• OpenShift Pipeline Plugin Visit the upstream repository, which demonstrates example usage of the plugin's capabilities with the OpenShift Sample Job included in this image. For more details visit the Jenkins plugin website. Future development of this plugin is being deprioritized in favor of the OpenShift Client Plugin detailed below. But this plugin is still supported for existing users who have yet to finish migrating to OpenShift Client Plugin. It also serves as an option if the use of the oc binary from your Jenkins jobs is not viable for some reason (we are actually curious if such use cases in fact exist), as it interacts with OpenShift via HTTP REST. Remember though only a subset of the functionality provided by oc is available from this plugin.

• OpenShift Client Plugin Visit the upstream repository as well as the Jenkins plugin wiki. With the lessons learned from OpenShift Pipeline Plugin, as well as adjustments to the rapid evolutions of both Jenkins and OpenShift, this plugin, with its fluent styled syntax and use of the oc binary (exposing all the capabilities of that command), is the preferred choice for interacting with OpenShift via either Jenkins Pipeline or Freestyle jobs.

• OpenShift Sync Plugin Visit the upstream repository as well as the Jenkins plugin wiki. This plugin facilitates the integration between the OpenShift Jenkinsfile Build Strategy and Jenkins Pipelines. It also facilitates auto-configuration of the slave pod templates for the Kubernetes Plugin. See the OpenShift documentation for more details.

• OpenShift Login Plugin Visit the upstream repository as well as the Jenkins plugin wiki. This plugin integrates the authentication and authorization of your Jenkins instance with you OpenShift cluster, providing a single sign-on look and feel. You'll sign into the Jenkins server using the same credentials that you use to sign into the OpenShift Web Console or interact with OpenShift via the oc CLI. See the OpenShift documentation for more details.

For the above OpenShift Jenkins plugins, each of their READMEs have specifics unique to each of them on how to use and if so desired contribute to their development. That said, there is a good deal of commonality and shared infrastructure related to developing, creating new versions, and ultimately updating the images of this repository with those new versions. If you would like to understand the specifics of that process, please visit our plugin contribution guide.

• Kubernetes Plugin Though not originated out of the OpenShift organization, this plugin is invaluable in that it 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 this 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

Authenticating into a Jenkins server running within the OpenShift Jenkins image is controlled by the OpenShift Login plugin, taking into account:

• Whether or not the container is running in an OpenShift Pod
• How the environment variables recognized by the image are set

See the OpenShift Login plugin documentation for details on how it manages authentication.

However, when the default authentication mechanism for Jenkins is used, if you are using the OpenShift Jenkins image, you log in with the user name admin, supplying the password specified by the JENKINS_PASSWORD environment variable set on the container. If you do not override JENKINS_PASSWORD, the default password for admin is password.

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=2
  

• CentOS based image

  $ cd jenkins
  $ make test VERSION=2
  

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.