Re: Hosting first-party kernel.org container images

[Ben Copeland <ben.copeland@linaro.org>]

Hello Guillaume,

On Fri, 19 Dec 2025 at 13:37, Guillaume Tucker <gtucker@gtucker.io> wrote:
>
> Hi Konstantin, Arnd et al,
>
> This is a follow-up from the series about adding a scripts/container
> tool [1] to run kernel builds in containers.  As per the discussion
> at Plumbers last year and the summary I put in a blog post [2], it
> would be great to have container images with kernel.org toolchains
> hosted upstream.  This can mean several things, so let's break it
> down into a set of potential options to choose from:
>
>
> * Containerfiles Git repository
>
> There is currently a PoC repository on GitLab with a Makefile and a
> number of Containerfiles to build a set of images:
>
>      https://gitlab.com/gtucker/korg-containers

TuxMake already provides container images with kernel.org toolchains
(korg-gcc 8-15, korg-clang 11-22). The Dockerfiles are maintained at
[1]

Since TuxMake is now part of KernelCI and already referenced in the
kernel documentation you pushed [2], it seems like a natural home for
this rather than starting fresh, or having two places for images.

>
> It can be improved in many ways since this is an early PoC.  The key
> decision to make here, if we do want to have container images
> supported upstream, is how to manage these files or a derived
> implementation.
>
> One option is to add it to the kernel tree itself under e.g.
> tools/container.
>
> Another option is to add a separate repository on git.kernel.org,
> which I believe would be a better approach as there aren't any direct
> dependencies on the kernel tree itself.
>
> A third option might be to keep it alongside any recipes used to
> produce the existing kernel.org toolchain tarballs although I'm not
> entirely sure how that's managed - something for Arnd to judge I
> guess.
>
> A last option would be to keep it on GitLab or move it to GitHub
> which would provide some CI/CD tools for building the images but I
> doubt this is something viable for the kernel community as it would
> create some vendor lock-in.
>
>
> * Container image registry
>
> This is where things get a bit more complicated.  As far as I'm
> aware, there aren't any container registries hosted in the kernel.org
> infrastructure at the moment.  A classic option would be to push the
> images to an established one e.g. Docker Hub (docker.io) or the
> Google Artifact Registry.  GitLab and GitHub also provide theirs of
> course.  I believe there is still a free plan for community projects
> to host images on docker.io and that would be the easiest from a user
> point of view e.g. "docker pull kernel.org/gcc".  It comes with some
> maintenance burden of course, and Docker Hub has a history of
> changing its policies quite unexpectedly so it's not entirely
> future-proof.

The images are hosted on Docker Hub (https://hub.docker.com/u/tuxmake)
with ECR Public as fallback:

      docker pull tuxmake/arm64_korg-gcc-14
      docker pull tuxmake/x86_64_korg-clang-22

Happy to discuss how we can align efforts here. But to me, it makes
sense for KernelCI to be the place for these images (or for us to have
a single place and a single set of images).

[1] https://github.com/kernelci/tuxmake/tree/master/support/docker
[2] https://www.kernel.org/doc/html/next/dev-tools/container.html

Regards,

Ben

>
> A classic alternative would be to host a dedicated service
> e.g. registry.kernel.org and have the images managed there.  This
> would obviously involve higher sysadmin efforts and add scalability
> issues but would decouple it from external providers.
>
> Then a third option would be to host the container images as OCI
> tarball dumps alongside the toolchain tarballs.  They can then be
> downloaded and imported with "docker image load" or any other
> container runtime.  The only infrastructure resources needed would be
> storage space.  This is of course suboptimal as all the layers get
> bundled together and users would have to manage these images
> themselves, but it's very effective from a kernel.org sysadmin point
> of view.
>
>
> There are undoubtedly other ways to look at this, I'm curious to know
> what people think.  The benefits of having readily-available
> container images upstream appear to be pretty clear, several
> maintainers have expressed their support already.  It's all down to
> how much these benefits can outweigh the upstream maintenance costs.
> Maybe this can be done in two steps, first with just the
> Containerfiles and later on a full solution to host the actual
> images.
>
> Best wishes,
> Guillaume
>
> [1] https://lore.kernel.org/all/cover.1766061692.git.gtucker@gtucker.io/
> [2] https://gtucker.io/posts/2024-09-30-korg-containers/