Re: [RFC] container images for migration-test

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Oct 14, 2026 at 02:56:46PM -0300, Fabiano Rosas wrote:
> Daniel P. Berrangé <berrange@redhat.com> writes:
> 
> > On Mon, Sep 14, 2026 at 08:58:09PM -0300, Fabiano Rosas wrote:
> >> Hi, I just wanted to share and ask for feedback on some container images
> >> I've been building as part of my testing of migration pull-requests.
> >> 
> >> From a Dockerfile from ./tests/docker/dockerfiles/ I'm producing the
> >> following:
> >> 
> >> $ docker images
> >> qemu-build-base:11.0.0                        b6efa198e93a        5.8GB
> >> qemu-rootfs-base:11.0.0                       72bcb5418f4d       4.08GB
> >> qemu:11.0.0                                   018a3f0f4dcc          2GB
> >
> > snip
> >
> >> 2) Neither the QEMU build nor the distro repos are reliable enough to
> >> allow me to just "go back in time" and rebuild at any moment, I need to
> >> keep the artifacts cached to avoid rebuilding. Otherwise it comes time
> >> to send a PR and I discover that some python piece has changed or the
> >> distro messed up the older repository.
> >
> > Yes, in general building old QEMU on new distros periodically
> > hits trouble.  If building old QEMU, better reliability is
> > achieved by using a distro release that was from the same
> > timeframe as QEMU.  Is using containers targetting such old
> > distro versions not an option ? The tests/docker/dockerfiles
> > from the old QEMU branch ought to work ?
> >
> 
> Yes, I'm doing just that. Some tweaks are needed still. For instance, my
> script has something like this:
> 
>   dockerfile="tests/docker/dockerfiles/opensuse-leap.docker"
> 
>   sed -i 's/ncurses-devel//' $dockerfile
> 
>   if [ "$tag" = "10.1.0" ]; then
>       sed -i 's/libLLVM19//' $dockerfile
>   fi

If that's needed, shouldn't we patch the QEMU stable branch ? I
would have thought that would be a problem for doing releases on
stable if the containers have bugs ?

> > How far back in time do you need/want to go for migration
> > testing ?  Is it sufficient to merely target versions for
> > which mjt is still doing active maint work, so we can
> > expect the containers to still work.
> >
> 
> I'm currently testing against the previous 3 releases. I think 2
> releases is probably enough.

I guess if we test   X -> Y and then later test Y -> Z, then
we have transitively validated X -> Z. So in theory only 1
historical release is enough, but it makes sense to test one
or two more variants just in case.

With regards,
Daniel
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