Upcoming CI changes - transition to VM based CI

[Ben Cooksley]

On Tue, Jun 3, 2025 at 9:03 AM Albert Astals Cid <aacid at kde.org> wrote:

> El dilluns, 2 de juny del 2025, a les 13:39:21 (Hora d’estiu d’Europa
> central), Ben Cooksley va escriure:
> > Hi all,
> >
> > For some time now we have had a variety of issues with our Docker/Podman
> > based CI builds. These have included the lack of GUI test support on
> > Windows, periodic crashes on FreeBSD, poor IO performance of Windows
> > builds, issues supporting builds for Flatpak and Snaps and inability to
> > support either builds or tests where elevated privileges or system
> session
> > resources are needed.
> >
> > In addition to this we've had issues where Linux CI builds have the
> > capability to trigger OOM events on the CI hosts, which in turn takes out
> > Windows and (less often) FreeBSD builders. While this does not occur too
> > often, it does happen from time to time and eventually negatively impacts
> > the build queue for those platforms.
> >
> > The need to have dedicated VMs for FreeBSD and Windows on our builders
> also
> > makes setting up of a CI build node for KDE software a more complicated
> and
> > time intensive task than it otherwise needs to be (and means that the
> > amount of systems to care for increases by 3 for every CI node we add).
> >
> > While individually relatively minor, together these issues more than
> > justify making a significant change to the way we run our CI system - in
> > this case transitioning from container based builds to VM based builds.
> >
> > These builds will still take place on dedicated hardware that we control,
> > however instead of taking place within a container (managed by Podman on
> > Linux and FreeBSD, or Docker on Windows) they will instead take place
> > within a VM using a copy-on-write disk image.
> > VM based builds will unfortunately take a little longer to start (it
> takes
> > ~10 seconds for a VM from any of Linux, FreeBSD or Windows to boot on my
> > personal system) however the benefits we gain should more than outweigh
> > this small downside.
> >
> > This has been under development for the past couple of weeks and is now
> > reaching the point where the only remaining steps are to get it
> integrated
> > with the Gitlab CI agent (gitlab-runner) for which prototype code is
> > already in place, and complete porting of our images over. Once that
> > happens a complete rebuild of all of our builders will be swiftly
> > undertaken to transition them completely over to the new VM based
> > infrastructure.
> >
> > Specs wise, at this time it is planned for each spawned standard VM to be
> > provided with 2/3's of the system CPU cores (so 12 cores), 16GB RAM and
> > 100GB of disk space (although some of that will be occupied by the system
> > image - approximately 10GB for standard Linux builds and ~30GB or so for
> > Windows builds). There will be a higher resource tier available for
> certain
> > builds however that will be on request only and would need to be
> justified
> > (such as Craft needing to build QtWebEngine).
> >
> > As launching VMs is not the most efficient approach for all workloads,
> > limited support for running Docker containers will be preserved, however
> > this support is primarily intended for running linters, sanity checks and
> > website builds, and is not intended for running general CI/CD builds.
> >
> > The tooling used by the CI nodes to run VMs is something that should be
> > fairly trivial for people to run on their own local system should they
> wish
> > to run any of those images (say for FreeBSD or Android), although you
> will
> > need to setup libvirt yourself (SUSE has very good instructions for this,
> > Debian less so as their instructions lack installing the packages needed
> to
> > provide UEFI and TPM support). The tooling itself was merged this evening
> > to sysadmin/ci-images (vm-common/ folder) and can be used with the VM
> > images found at https://storage.kde.org/vm-images/
> >
> > There is however one downside to this - Qt 5 support.
> >
> > Over the past few months distributions have been steadily removing
> packages
> > and other supporting infrastructure needed to keep Qt 5 builds alive. In
> > the case of Windows, support for the entire Qt 5 tree has been
> unmaintained
> > for some time. For FreeBSD and SUSE a significant number of packages have
> > been removed - which in the case of SUSE also includes packages needed to
> > support the building of KJS.  Accordingly, because builds of Frameworks
> are
> > a first stepping stone to support building anything else, it will not be
> > possible for us to produce Qt 5 based VM build images for any of the 3
> > platforms.
> >
> > We will therefore have to remove Qt 5 support from the CI system with the
> > transition to VM based CI.
>
> From previous discussions I had the impression this was only for things
> that
> wanted to create packages and not for "want to have CI to compile/run
> tests".
>
> Can you confirm you are proposng a total annihilation of Qt5 support in
> our
> CI?
>

At the time we had that discussion it was still possible to build some of
the Qt 5 images, however that is no longer the case - all of them now fail
to build.

In the case of the suse-qt515 image, the removal of libpcre in SUSE means
it is no longer possible to build KJS.
Consequently, we're no longer able to build all Frameworks (making 'kf5'
branch CI for Frameworks non-functional) so there isn't much point in
looking further to support Qt 5 on Linux.

For FreeBSD the story is much the same as SUSE - packages are being removed
as apps upgrade to Qt 6 and the Qt 5 version of libraries becomes surplus
to requirements.

For Windows the continued operation of that CI has only been possible
because our existing images are still around - new ones cannot be built.
That has been the case for a significant amount of time now, and it is not
worth the investment to fix it as everyone who works on Windows has moved
on to Qt 6.

In essence there is little we can do to keep this alive - distributions are
removing support so we must follow suit.

The correct course of action is to accelerate the porting of the remaining
applications, not to delay and keep Qt 5 alive.


>
> Cheers,
>   Albert
>

Regards,
Ben


>
> >
> > Please let me know if there are any questions on the above.
> >
> > Thanks,
> > Ben
>
>
>
>
>
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