Missing "Uninstall" plugin section

[dduportal]

Describe your use-case which is not covered by existing documentation.

The section https://github.com/jenkinsci/docker#preinstalling-plugins describes pretty well how to add plugin to a Jenkins controller image.

The "install / update" plugin is really easy, but the removal of a plugin can be cumbersome if you are not an expert in "how the image and its entrypoint works".

As a user, I would like to have a simple example on how to properly remove a plugin on my existing installation.

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

The section should give the following insights:

• Plugin removal should start by the plugins.txt (or equivalent jenkins-plugin-cli call) on the custom Dockerfile. The plugin should then be absent from the /usr/share/jenkins/ref/plugins directory

  • A command for self-diagnosing this step should be provided

• However, the plugin is still in the $JENKINS_HOME/plugins/ (data volume or bind mounted volume) because the entrypoint script does NOT delete plugins. We have to tell end user to remove the plugin (either through the Jenkins UI or by removing the files and restarting the container)

As discussed with @gounthar and @MarkEWaite during the SIG Platform meeting, the example of removing the "WMI" windows-slave plugin could be a great example for this documentation