Re: Building container images with nix2container

[Simon Tournier]

Hi lewo,

On lun., 26 févr. 2024 at 11:09, Antoine Eiche <lewo@abesis.fr> wrote:

> Does your built images contains several layers?

This had recently been introduced.

        0cf75c9b2f23869201144917cea7f6ad49683d3d
        AuthorDate: Tue Dec 26 03:54:12 2023 +0300
        CommitDate: Mon Jan 8 21:04:44 2024 +0300

> nix2container uses an heuristic to group store paths into layers. The
> goal is to share common layers between images and to avoid full image
> rebuild when only a storepath differs.

Well, I have not followed on which strategy Guix relies.  What is the
one of nix2container?  The one described here:

    https://grahamc.com/blog/nix-and-layered-docker-images/

> Do you write the image tarball into your store when you build an image?
>
> nix2container is able to build layers on the fly from the Nix store. The
> goal is to reduce IOs and storage. Instead of writing an image tarball
> into the store, it generates a script which stream layers from store
> paths to the destination (a Docker registry, the Docker deamon, Podman
> or a file).

To my knowledge, this is not implemented in Guix.  And indeed, it could
improve the dance.  Currently, it reads:

    docker load < $(guix pack -f docker …)


Cheers,
simon