[ovirt-devel] gerrit+ci improvement proposal
Oved Ourfali
ovedo at redhat.com
Thu Jun 4 07:03:02 UTC 2015
----- Original Message -----
> From: "Eyal Edri" <eedri at redhat.com>
> To: "Sandro Bonazzola" <sbonazzo at redhat.com>
> Cc: infra at ovirt.org, devel at ovirt.org
> Sent: Thursday, June 4, 2015 9:46:40 AM
> Subject: Re: [ovirt-devel] gerrit+ci improvement proposal
>
>
>
> ----- Original Message -----
> > From: "Sandro Bonazzola" <sbonazzo at redhat.com>
> > To: "Eyal Edri" <eedri at redhat.com>, "Max Kovgan" <mkovgan at redhat.com>
> > Cc: devel at ovirt.org, infra at ovirt.org
> > Sent: Thursday, June 4, 2015 9:11:10 AM
> > Subject: Re: [ovirt-devel] gerrit+ci improvement proposal
> >
> > Il 03/06/2015 21:46, Eyal Edri ha scritto:
> > >
> > >
> > > ----- Original Message -----
> > >> From: "Max Kovgan" <mkovgan at redhat.com>
> > >> To: devel at ovirt.org
> > >> Cc: infra at ovirt.org
> > >> Sent: Wednesday, June 3, 2015 8:22:54 PM
> > >> Subject: [ovirt-devel] gerrit+ci improvement proposal
> > >>
> > >> Hi everyone!
> > >> We really want to have reliable and snappy CI: to allow short cycles and
> > >> encourage developers to write tests.
> > >>
> > >> # Problem
> > >>
> > >> Many patches are neither ready for review nor for CI upon submission,
> > >> which
> > >> is OK.
> > >> But running all the jobs on those patches with limited resources results
> > >> in:
> > >> overloaded resources, slow response time, unhappy developers.
> > >>
> > >> # Proposed Solution
> > >>
> > >> To run less jobs we know we don’t need to, thus making more resources
> > >> for
> > >> the
> > >> jobs we need to run.
> > >> We have been experimenting to make our CI stabler and quicker to respond
> > >> by
> > >> using gerrit flags. This has improved in both directions very well
> > >> internally.
> > >> Now it seems a good time to let all the oVirt projects to use this.
> > >> This solution indirectly promotes reviews and quick tests - “to fail
> > >> early”,
> > >> yet full blown static code analysis and long tests to run “when ready”.
> > >>
> > >> # How it works
> > >>
> > >> 2 new gerrit independent flags are added to gerrit.
> > >>
> > >> ## CI flag
> > >>
> > >> Will express patch CI status. Values:
> > >> * +1 CI passed
> > >> * 0 CI did not run yet
> > >> * -1 CI failed
> > >> Permissions for setting: project maintainers (for special cases) should
> > >> be
> > >> able to set/override (except Jenkins).
> > >>
> > >> ## Workflow flag
> > >>
> > >> Will express patch “workflow” state. Values:
> > >> * 0 Work In Progress
> > >> * +1 Ready For Review
> > >> * +2 Ready For Merge
> > >> Permissions for setting: Owner can set +1, Project Maintainers can set
> > >> +2
> > >>
> > >> ## Review + CI Integration:
> > >>
> > >> Merging [“Submit” button to appear] will require: Review+1, CI+1,
> > >> Workflow+2
> > >> Patch lifecycle now is:
> > >> ---------------------------------------------------------------
> > >> patch state |owner |reviewer |maintainer |CI tests |pass
> > >> ---------------------------------------------------------------
> > >> added/updated |- |- |- |quick |CI+1
> > >> review |Workflow+1|Review+1 |- |heavy |CI+1
> > >> merge ready |- |- |Workflow+2 |gating |CI+1
> > >> merge |- |- |merge |merge |CI+1
> > >>
> > >> Changes from current workflow:
> > >> Owner only adds reviewers, now owner needs to set "Workflow+1" for the
> > >> patch
> > >> to be reviewed, and heavily auto-tested.
> > >> Maintainer now needs to set "Workflow+2" and wait for "Submit" button to
> > >> appear after CI has completed running gating tests.
> > >>
> > >>
> > >> Next step will be to automate merge the change after Workflow+2 has been
> > >> set
> > >> by the Maintainer and gating tests passed.
> > >>
> > >>
> > >> ## Why now?
> > >>
> > >> It is elimination of waste. The sooner - the better.
> > >> The solution has been used for a while and it works.
> > >> Resolving the problem without gerrit involved will lead to adding
> > >> unreliable
> > >> code into jobs, and will still be prone to problems:
> > >> Just recently, 3d ago we’ve tried detecting what to run from jenkins
> > >> relying only on gerrit comments so that upon Verified+1, we’d run the
> > >> job.
> > >> We could not use “Review+1”, because it makes no sense at all, so we
> > >> left
> > >> the job to set Verified+1.
> > >> Meaning - re-trigger itself immediately more than 1 times.
> > >>
> > >> Jenkins and its visitors very unhappy, and we had to stop those jobs,
> > >> clean
> > >> up the queue, and spam developers.
> > >>
> > >> ## OK OK OK. Now what?
> > >>
> > >> Now we want your comments and opinions before pushing this further:
> > >> Please participate in this thread, so we can start trying it out.
> > >> Ask, Suggest better ideas, all this is welcome.
> > >>
> > >>
> > >> Best Regards!
> > >>
> > >>
> > >> N.B.
> > >> Of course, this is not written in stone, in case we find a better
> > >> approach
> > >> on
> > >> solving those issues, we will change to it.
> > >> And we will keep improving so don't be afraid that it will be enforced:
> > >> if
> > >> this does not work out we will discard it.
> > >>
> > >> P.S.
> > >> Kudos to dcaro, most of the work was done by him, and most of this text
> > >> too.
> > >>
> > >
> > > +1 from me, releasing CI from running non critical and un-essential jobs
> > > will not only reduce load from ci,
> > > and shorted response time for developers, it will allow us to add much
> > > more
> > > powerful tests such as functional & system
> > > tests that actually add hosts and run VMs, improving our ability to find
> > > regression much more effectively.
> > >
> > > Another benefit to consider is saving reviewers time. I.e not only
> > > jenkins
> > > benefits from Worklow+1, but also human reviewers.
> > > Instead of looking at a patch that is too early to be reviewed, the
> > > author
> > > can set the Workflow+1 when the code is ready to review
> > > (even if he didn't verified it yet), thus saving time to other reviewers
> > > -
> > > for example people can add an email rule
> > > to alert them only when they are added to patches that have Workflow+1,
> > > and
> > > not before.
> >
> > For human reviewers I suggest to keep using drafts until the patch is
> > finished.
>
> keep using? how many developers do you know are working with drafts until
> their patch is ready?
> i agree if everyone would use drafts load on jenkins was already much lower,
> unfortunately its not the case.
>
IMO we don't need the "workflow" flag.
I'm okay with CI not running on "drafts". And yes... we do use them.
We can try and educate people to use them more where needed.
Drafts should be widely used in first-phase development, and less on bug-fixes.
In addition, I think the patch owners shouldn't add reviewers, unless they need their input in the stage of the development.
Once they want input, they should add reviewers.
1. So, if the patch is draft then no CI runs on it.
2. Once it turns into non-draft, you can run "light-CI" on it.
3. Once the patch has at least one +1 from a (human) reviewer, then it should run the "heavy" CI.
4. Once the patch has +1 from heavy CI, and +2 from reviewer (maintainer), then it can be merged.
That's the process we have today, with slight change on when to run the CI and what CI to run (no CI on drafts, light CI on non-draft, heavy CI on +1 patches).
> > Once it's finished and humans reviewed the logic of the patch, Workflow+1
> > should be triggered allowing automation to check the correctness of the
> > patch.
> > IMHO there's no reason for wasting CI time on patches that will be correct
> > from an automation point of view but nacked by reviewers. Especially if the
> > patches are part of a big patchset.
> >
> >
> > >
> > > And one final note, for Workflow+2 -> this is a preparation for a gating
> > > system, like Zuul used by openstack, that in the future
> > > we might use as automatic merger pending passing a verification step.
> > > this
> > > will prevent errors that happen sometimes
> > > post merge due to conflicts or other issues, and will be another level of
> > > validation before final merge.
> > > But as max said, its all part of the plan and we'll test it of course
> > > before implementing to see its value.
> > >
> > >
> > >>
> > >>
> > >>
> > >> Max Kovgan
> > >>
> > >> Senior Software Engineer
> > >> Red Hat - EMEA ENG Virtualization R&D
> > >> Tel.: +972 9769 2060
> > >> Email: mkovgan [at] redhat [dot] com
> > >> Web: http://www.redhat.com
> > >> RHT Global #: 82-72060
> > >>
> > >> _______________________________________________
> > >> Devel mailing list
> > >> Devel at ovirt.org
> > >> http://lists.ovirt.org/mailman/listinfo/devel
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> > >
> >
> >
> > --
> > Sandro Bonazzola
> > Better technology. Faster innovation. Powered by community collaboration.
> > See how it works at redhat.com
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