Re: [PATCH 0/5] QEMU Gating CI

[Erik Skultety]

On Thu, Apr 23, 2020 at 11:28:21PM +0200, Philippe Mathieu-Daudé wrote:
> On 4/23/20 7:13 PM, Daniel P. Berrangé wrote:
> > On Thu, Apr 23, 2020 at 01:04:13PM -0400, Cleber Rosa wrote:
> > > ----- Original Message -----
> > > > From: "Peter Maydell" <address@hidden>
> > > > To: "Markus Armbruster" <address@hidden>
> > > > Cc: "Fam Zheng" <address@hidden>, "Thomas Huth" <address@hidden>, 
> > > > "Beraldo Leal" <address@hidden>, "Erik
> > > > Skultety" <address@hidden>, "Alex Bennée" <address@hidden>, "Wainer 
> > > > Moschetta" <address@hidden>,
> > > > "QEMU Developers" <address@hidden>, "Wainer dos Santos Moschetta" 
> > > > <address@hidden>, "Willian Rampazzo"
> > > > <address@hidden>, "Cleber Rosa" <address@hidden>, "Philippe 
> > > > Mathieu-Daudé" <address@hidden>, "Eduardo
> > > > Habkost" <address@hidden>
> > > > Sent: Tuesday, April 21, 2020 8:53:49 AM
> > > > Subject: Re: [PATCH 0/5] QEMU Gating CI
> > > > 
> > > > On Thu, 19 Mar 2020 at 16:33, Markus Armbruster <address@hidden> wrote:
> > > > > Peter Maydell <address@hidden> writes:
> > > > > > I think we should start by getting the gitlab setup working
> > > > > > for the basic "x86 configs" first. Then we can try adding
> > > > > > a runner for s390 (that one's logistically easiest because
> > > > > > it is a project machine, not one owned by me personally or
> > > > > > by Linaro) once the basic framework is working, and expand
> > > > > > from there.
> > > > > 
> > > > > Makes sense to me.
> > > > > 
> > > > > Next steps to get this off the ground:
> > > > > 
> > > > > * Red Hat provides runner(s) for x86 stuff we care about.
> > > > > 
> > > > > * If that doesn't cover 'basic "x86 configs" in your judgement, we
> > > > >    fill the gaps as described below under "Expand from there".
> > > > > 
> > > > > * Add an s390 runner using the project machine you mentioned.
> > > > > 
> > > > > * Expand from there: identify the remaining gaps, map them to people /
> > > > >    organizations interested in them, and solicit contributions from 
> > > > > these
> > > > >    guys.
> > > > > 
> > > > > A note on contributions: we need both hardware and people.  By people 
> > > > > I
> > > > > mean maintainers for the infrastructure, the tools and all the 
> > > > > runners.
> > > > > Cleber & team are willing to serve for the infrastructure, the tools 
> > > > > and
> > > > > the Red Hat runners.
> > > > 
> > > > So, with 5.0 nearly out the door it seems like a good time to check
> > > > in on this thread again to ask where we are progress-wise with this.
> > > > My impression is that this patchset provides most of the scripting
> > > > and config side of the first step, so what we need is for RH to provide
> > > > an x86 runner machine and tell the gitlab CI it exists. I appreciate
> > > > that the whole coronavirus and working-from-home situation will have
> > > > upended everybody's plans, especially when actual hardware might
> > > > be involved, but how's it going ?
> > > > 
> > > 
> > > Hi Peter,
> > > 
> > > You hit the nail in the head here.  We were affected indeed with our 
> > > ability
> > > to move some machines from one lab to another (across the country), but 
> > > we're
> > > actively working on it.
> > 
> > For x86, do we really need to be using custom runners ?
> > 
> > With GitLab if someone forks the repo to their personal namespace, they
> > cannot use any custom runners setup by the origin project. So if we use
> > custom runners for x86, people forking won't be able to run the GitLab
> > CI jobs.
> > 
> > As a sub-system maintainer I wouldn't like this, because I ideally want
> > to be able to run the same jobs on my staging tree, that Peter will run
> > at merge time for the PULL request I send.
> > 
> > Thus my strong preference would be to use the GitLab runners in every
> > scenario where they are viable to use. Only use custom runners in the
> > cases where GitLab runners are clearly inadequate for our needs.
> > 
> > Based on what we've setup in GitLab for libvirt,  the shared runners
> > they have work fine for x86. Just need the environments you are testing
> > to be provided as Docker containers (you can actually build and cache
> > the container images during your CI job too).  IOW, any Linux distro
> > build and test jobs should be able to use shared runners on x86, and
> > likewise mingw builds. Custom runners should only be needed if the
> > jobs need todo *BSD / macOS builds, and/or have access to specific
> > hardware devices for some reason.

Not just ^that, you also want custom VM runners to run integration tests, e.g.
in libvirt, we'd have to put systemd and a lof of other cruft into the
container to be able to run the tests at which point you must ask yourself,
whyt not go with a VM instead in which case we're limited in terms of
infrastructure...

> 
> Thanks to insist with that point Daniel. I'd rather see every configuration
> reproducible, so if we loose a hardware sponsor, we can find another one and
> start another runner.
> Also note, if it is not easy to reproduce a runner, it will be very hard to
> debug a reported build/test error.

(Thanks for bringing ^this point up Philippe)

...However, what we've been actively working on in libvirt is to extend the
lcitool we have (which can spawn local test VMs) to the point where we're able
to generate machines that would be the reproducible. Right now I'm playing with
cloud-init integration with lcitool (patches coming soon) that would allow us
to use the same machines locally as we'd want to have in, say, OpenStack and
share them as compressed images, so even when updated/managed by lcitool
locally, you'd get the same environment.

Regards,

-- 
Erik Skultety