[ovirt-devel] Adding s390 support to oVirt

[Dan Horák]

On Fri, 24 Nov 2017 13:16:53 +0200
Barak Korren <bkorren at redhat.com> wrote:

> On 24 November 2017 at 11:05, Viktor Mihajlovski
> <mihajlov at linux.vnet.ibm.com> wrote:
> > On 21.11.2017 11:26, Dan Horák wrote:
> > [...]
> >>> qemu s390x emulation does not work with code compiled for z12.
> >>> Would a real virtual machine be what you need?
> >>> The Fedora team DOES have access to a z13. Not sure how much
> >>> resources are available, but can you contact Dan Horak (on cc) if
> >>> there is enough spare capacity.
> >>
> >> Christian is right, we have a publicly accessible guest running
> >> Fedora on the Marist College z13 mainframe. It's currently used by
> >> ~5 projects (for example glibc and qemu) as their build and CI
> >> host, so adding another project depends how intensive ovirt's
> >> usage would be.
> > As a first step one could only build the packages needed for the KVM
> > host. At this point in time that would be vdsm and ovirt-host, both
> > are building rather quickly.
> > It should be possible to ensure that only these are built on a s390
> > system using appropriate node filters.
> > [...]
> 
> We can get more accurate data by looking at the ppc64c build history
> (We support ppc64le only for hypervisor usage, similar to what is
> intended for s390).
> Here is the history for vdsm:
> http://jenkins.ovirt.org/job/vdsm_master_build-artifacts-el7-ppc64le/buildTimeTrend
> (~20 builds a day taking 1-2 minutes each)
> And here is the one for ovirt-host:
> http://jenkins.ovirt.org/job/ovirt-host_master_check-patch-el7-ppc64le/buildTimeTrend
> (only 1 build in history, taking 3-4 minutes)
> 
> Looking at what else we have building on ppc64le:
> http://jenkins.ovirt.org/search/?q=master_build-artifacts-el7-ppc64le
> I can also see ioprocess with is a vdsm dependency, and the SDK which
> is probably not really needed.
> So for ioprocess:
> http://jenkins.ovirt.org/job/ioprocess_master_build-artifacts-el7-ppc64le/buildTimeTrend
> I'd say its very rarely built.
> 
> So we end up with ~20 1-2 minute builds a day (Timed but the amount of
> Fedora versions we want to support, but what will probably be just
> one), with the rest being a statistical error...
> 
> I wonder about sharing a VM with other project though. We do use mock
> for running the build script so the build itself should be fairly
> isolated, but we have some of our own wrapper scripts around mock that
> do things trying to keep build dependencies in the chroot cache over
> time. We're also incompatible with mock's new systemd-nspawn backend,
> so we force it to work with the older chroot-based backend. If other
> projects are using mock as well, I wonder if we may end up with race
> conditions arising from shared use of /var/lib/mock.

it should work fine
 
> Bottom line - we may end up being a little noisy neighbours if we
> share a VM, but we can try that and see what happens, how to we move
> foreward with trying that?

ok, I'm pretty sure we can make it work :-) Please send me your
public SSH key and preferred username, then I'll set up you an account
for you and we can work on the remaining details.


		Dan