Problem:

Currently multi-branch pipeline builds & organizational builds require you to have a Jenkinsfile checked in for each branch/project that is to be built. The associated checked in Jenkinsfile will be used for the build job. There is no way to use a different discovery mechanism for each job, and checkout a Jenkinsfile from source as you can with a standard pipeline build job.

How it effects my team:

My team is using the same Jenkinsfile for all of our builds thanks to leveraging a gradle plug-in we wrote which defines the tasks needed for each project. We want to adopt multi-branch pipeline builds & organizational builds, but the associated maintenance of having to update 20+ Jenkinsfile's when we want to make a change to the Jenkinsfile is too much work. Therefore, we are not adopting multi-branch or organizational pipeline jobs at this time and will be sticking to standard Pipeline jobs as it supports Jenkinsfile checkout.

Purposed Solution:

Since you already support Jenkinsfile checkout for Pipeline Builds, why not support it for multi-branch and organizational builds?

Issue to implement this feature currently:

• Discovery 
  • Right now discovery of a project/branch for a build job is based off whether or not a Jenkinsfile is checked in for the associated project/banch. You could create behavior as such: 
    • If there is a Jenkinsfile, create a build job for that project/branch and use it. If there isn't one and there is some other property existing(some string in a readme, a special badge, etc.) create a build job and checkout the Jenkinsfile from a provided git repo. This supports one off cases where a project might need to do something special but allows for better maintenance for projects sharing a Jenkinsfile.