bug#59846: "Running Guix in a Virtual Machine" documentation unclear/incomplete/wrong

[宋文武]

Ian Eure <ian@retrospec.tv> writes:

> I’m trying to explore Guix System by running it in a VM on my computer
> which runs Debian.  I’m interested in some of the Guix ideas, but not
> ready to do a bare-metal install.

Hello!
>
> I found the download page[1] and got a copy of the QEMU image, then
> clicked "Installation instructions"[2].  These instructions didn’t
> work, because they’re incomplete and/or unclear and/or wrong and/or
> not really installation instructions in the way one might assume.
> Since I don’t really know anything about Guix (which is why I’m
> reading the documentation and test driving it in a VM), I’m not sure
> which one-or-more of these it may be.

Sorry for the not very helpful documentation, I'd say write good
documentation is very hard...
>
> Specifically:
>
>> To enable SSH inside a VM you need to add an SSH server like
>> openssh-service-type to your VM (see openssh-service-type).
>
> The documentation doesn’t say *how* to do that.  The
> openssh-service-type link[3] takes me to a large page of code
> documentation for every possible networking service, instead of the
> openssh-service-type one specifically.  This documentation describes
> *what* the service type and its many configuration options is, but is
> silent on *how* to make use of it.

This openssh-service-type should be added into the system configuration
file, it's /run/current-system/configuration.scm in the pre-built qemu
image or the file passed to 'guix system vm-image' when built your own
image.  The configuration file is a scheme (guile) file, the detail is
in the section "10.1 Using the configuration System".

>
> It continues:
>
>> In addition you need to forward the SSH port, 22 by default, to the
>> host. You can do this with
>> $(guix system vm config.scm) -nic
>> user,model=virtio-net-pci,hostfwd=tcp::10022-:22
>
> I’m really not sure what this is supposed to be doing.  It can’t run
> on my Debian host, since there’s no guix command.  It errors inside
> the VM, since it can’t find a config.scm file; and I don’t see an
> obvious config.scm file anywhere inside the VM that it might be
> looking for.
>
> I *suspect* that this documentation is actually targeted at running a
> Guix System VM on an existing Guix host.  Which is a chicken-and-egg
> problem, if I’ve already installed Guix, I don’t need to follow
> instructions to install it.

Well this 10.16 target both running a pre-built qcow guix system image
and running a 'guix system vm' built one.  But it's not self contained,
as the service things lacking commands for the former as you reported,
and the later case assume you already have guix installed (not the guix
system though).

Hope it helps!