Re: Guix Docker image inflation

[Leo Famulari]

On Fri, May 29, 2020 at 12:19:46PM -0400, Stephen Scheck wrote:
> The previous day's Docker image is used as the base for the new one being
> built - the image is pulled from Docker Hub, `guix pull` is run inside it,
> and a new
> image is "committed" (Docker terminology for creating a new image from a
> file system snapshot).

I'm still not quite sure what you are doing (or what Docker does) so
please bear with me.

>     root@localhost /# du -h --max-depth=1 /gnu/store | egrep
> "guix-system$|guix-packages-base$|guix-[0-9a-f]*-modules$"
[...]
>     191M /gnu/store/l3amdz5xyhflg5wdzlxr2685dq5glic2-guix-527ab3125-modules
>     201M /gnu/store/5mhn1ynxvy7jihsknsnv3yspkkvc0r5s-guix-2e59ae238-modules

If I understand correctly, you should not need both of these directories
in a Guix VM image. The latter hashes are truncated guix.git commit
hashes and a VM image would only be based on a single one.

I recommend looking into why all these directories are being copied into
your images.

I figure you'd want to create each image with *only* the things
corresponding to the Git commit it's based on, but it sounds like they
are being created by copying the entire host image, which doesn't seem
right.

If the Docker images are being created by simply snapshotting the file
system of a non-ephemeral Guix system, that's probably not the right way
to do it. Is that what's going on?