Open Stack

Hongbin Lu <hongbin034 at gmail.com> writes:

> The goal of those patches is to move the job definitions and playbooks from
> openstack/zun to openstack/zun-tempest-plugin. The advantages of such
> change are as following:
>
> * Make job definitions closer to tempest test cases so that it is optimal
> for development and code reviews workflow. For example, sometime, we can
> avoid to split a patch into two repos in order to add a simple tempest test
> case.
> * openstack/zun is branched and openstack/zun-tempest-plugin is branchless.
> Zuul job definitions seem to fit better into branchless context.
> * It saves us the overhead to backport job definitions to stable branch.
> Sometime, missing a backport might lead to gate breakage and blocking
> development workflow.

Just a minor clarification: it's not always the case that branchless is
better.

Jobs which operate on repos that are branched are likely to be easier to
work with in the long run, as whatever configuration is specific to the
branch appears on that branch, instead of somewhere else.

Further, there shouldn't be a need to backport changes once the initial
jobs are set up.  In the future, when you branch master to stable/foo,
you'll automatically get a copy of the job that's appropriate for that
point in time, and you only need to update it if you're already updating
the software on that branch.  Older versions of jobs on stable branches
can continue to use their old configuration.

For jobs which should perform the same function on all branches, it is
easier to have those defined in branchless repos.  But in either case,
you can accomplish the same thing without moving jobs.  In a branched
repo, you can add a "branches: .*" matcher, and in a branchless repo,
you can add multiple variants for each branch.

The new v3-native devstack jobs are branched, and are defined in the
devstack repo.  They define how to set up devstack for each branch.  But
the tempest jobs (which build on top of the devstack jobs), are not
branched (just like tempest), since they are designed to run the same
way on all branches.

I don't know enough about the situation to recommend one way or the
other for Zun.  But I do want to emphasize that the best answer depends
on the circumstances.

-Jim