[ovirt-devel] gerrit+ci improvement proposal

Eyal Edri eedri at redhat.com
Thu Jun 4 07:01:41 UTC 2015



----- Original Message -----
> From: "Sandro Bonazzola" <sbonazzo at redhat.com>
> To: "Eyal Edri" <eedri at redhat.com>
> Cc: infra at ovirt.org, devel at ovirt.org
> Sent: Thursday, June 4, 2015 9:50:56 AM
> Subject: Re: [ovirt-devel] gerrit+ci improvement proposal
> 
> Il 04/06/2015 08:46, Eyal Edri ha scritto:
> > 
> > 
> > ----- 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?
> 
> We have ~350 drafts in gerrit so someone is using them :-)
> https://gerrit.ovirt.org/#/q/is:draft

good to know :)
so i guess even with that amount its still hard on jenkins.... 

> 
> > i agree if everyone would use drafts load on jenkins was already much
> > lower,
> > unfortunately its not the case.
> > 
> >> 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
> >>> _______________________________________________
> >>> Devel mailing list
> >>> Devel at ovirt.org
> >>> http://lists.ovirt.org/mailman/listinfo/devel
> >>>
> >>
> >>
> >> --
> >> Sandro Bonazzola
> >> Better technology. Faster innovation. Powered by community collaboration.
> >> See how it works at redhat.com
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> >> Infra at ovirt.org
> >> http://lists.ovirt.org/mailman/listinfo/infra
> >>
> >>
> >>
> 
> 
> --
> Sandro Bonazzola
> Better technology. Faster innovation. Powered by community collaboration.
> See how it works at redhat.com
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