From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ludovic =?UTF-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Subject: bug#39815: Sharing the store between a host and a guest
Date: Sun, 08 Mar 2020 23:16:17 +0100
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References: <87k147epvx.fsf@cassou.me> <87eeufdx2x.fsf@cassou.me>
 <20200228210753.GA30122@jasmine.lan>
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To: Leo Famulari <leo@famulari.name>
Cc: Damien Cassou <damien@cassou.me>, 39815@debbugs.gnu.org

Hi!

Leo Famulari <leo@famulari.name> skribis:

> As you found, what you get with `guix system vm` is read-only. Even
> though you copied build-vm.sh out of /gnu/store, it is just a shell
> script that refers to immutable data in the host /gnu/store.
>
> In order to share the store with a VM, you would need to also share the
> store database =E2=80=94 at least /var/guix/db if not all of /var/guix =
=E2=80=94 and
> also use the host's guix-daemon.
>
> It would be great to support your use case but I don't think anyone has
> worked on it yet.

Unfortunately, the Unix-domain socket in /var/guix/daemon-socket cannot
be shared over 9p AFAICS (with =E2=80=98guix system vm --expose=E2=80=99).

However, one thing that could work is to:

  1. in the guest, set GUIX_DAEMON_SOCKET=3Dguix://localhost:1234;

  2. set up QEMU port forwarding such that the guest=E2=80=99s port 1234 is
     somehow redirected to a port the host guix-daemon listens to (with
     =E2=80=98--listen=E2=80=99);

  3. share /var/guix with the guest.

It would be easier if Unix-domain sockets could be forwarded between the
host and the guest, but that doesn=E2=80=99t seem to be the case.  :-/

Ludo=E2=80=99.