Upcoming CI changes - transition to VM based CI

[Albert Astals Cid]

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?

Cheers,
  Albert

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