[bug#27521] [PATCH v5] build: Add iso9660 system image generator.

[Ludovic Courtès]

Heya,

Danny Milosavljevic <address@hidden> skribis:

>> Let’s add #:key (volume-id "GuixSD") and then:
>> 
>>   "--" "-volid" (string-upcase volume-id)
>
> It will fail when booting from CD because GuixSD can't find the root fs.

I don’t understand.  What I suggest here is equivalent to what was in
the patch (“-volid GUIXSD”), except that it avoids hard-coding the
value; it’s purely cosmetic.

>> Since this doesn’t have much to do with VMs, what about adding these
>> things to (gnu system iso9660) and (gnu build iso9660)?
>
> I'd be fine with it but I think adding it to system-disk-image (as this patch 
> does) is actually quite fitting - also, most of the stuff in there is not for 
> VMs either.  There are comments all over system-disk-image how it makes sure 
> not to set up the stuff for qemu but for real hardware.

Riiight.

>> We can also remove this ‘if’: it’s not natural for ‘qemu-image’ to
>> produce something that’s not a “QEMU image.”
>
> The patch context is misleading :)
>
> What it actually does is extend system-disk-image:
>
> (define (system-disk-image ... file-system-type)
>   ...
>   (if (= file-system-type "iso9660")
>       (iso9660-image ...)
>       (qemu-image)))

Oh OK, my bad.

> And if we want we could actually drop the entire non-iso9660 hydra image 
> (after testing, of course) because the grub-mkrescue image will boot from usb 
> stick as well.  So no need to have two different ones, actually.

You mean we could always use ‘grub-mkrescue’ instead of using it in one
case and using ‘grub-install’ & co. in the other case, right?

If that works, that sounds like a good idea to me.

>> Could you update “Invoking guix system” accordingly?
>
> We could replace the old "guix system disk-image" by a new "guix system 
> disk-image" which always creates the iso9660 image.
>
> Or are there other use cases of "guix system disk-image" ?

“guix system disk-image” is documented as returning a raw disk image,
which I think can be useful to keep.

So what about having:

  guix system vm-image   # qcow2
  guix system disk-image # raw
  guix system iso-image  # iso9660

?

Alternately, we could of course do:

  guix system image -f FORMAT

where FORMAT is one of the above.

Thoughts?

Perhaps it’s simpler to just add “guix system iso-image” in this patch
series and to think about the other option separately.

Ludo’.