Jookia <166...@gmail.com> skribis:
> I'd really like to discuss how much I needed to break to get the
> mapped-devices,
> file-systems and swap-devices to just 'work'. I even had to make a function to
> return a mapped-device type, and have swap-devices not do dependency tests
> since
> I technically don't use a device I've defined.
>
> It'd be much much better if I could do something like this in my services:
>
> (devices (list (file-system
> (uses '("/dev/matrix/root"))
> (creates '("/"))
> (device "/dev/matrix/root")
> (mount-point "/")
> (type "ext4"))
> (swap-device
> (uses '("/dev/mapper/matrix-swap"))
> (creates '()))
> (device "/dev/mapper/matrix-swap")
> (lvm-device
> (uses '("/dev/mapper/hdd" "/dev/sdb"))
> (creates '("/dev/matrix/"
> "/dev/mapper/matrix-swap"))
> (devices '("/dev/mapper/hdd" "/dev/sdb")))
> (luks-device
> (uses '("UUID=4dab5feb-d176-45de-b287-9b0a6e4c01cb"))
> (creates '("/dev/mapper/hdd"))
> (device "UUID=4dab5feb-d176-45de-b287-9b0a6e4c01cb")
> (name "hdd")
> (key-file "..."))))
>
> The issue is that it has a lot of duplicate information as I'm not sure
> uses/creates could always map to device/mount-point, like LUKS names. But this
> should satisfy most dependency issues automatically, I hope.
There are several issues being addressed here, IIUC:
1. How to refer to block devices (in the Unix sense) using UUIDs,
labels, or /dev file names in general, and not just for
‘file-system’.
2. How to determine dependencies among all these things.
3. How to handle mapped devices that lead to several /dev nodes, as is
the case with LVM.
For #1, I would like to have a general ‘device’ type, so one could
write:
(operating-system
;; …
(file-systems (list (file-system
(source (device (title 'label)
(name "my-root")))
(mount-point "/"))))
(swap (list (device
(title 'uuid)
(name (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))))
For that to work, we ideally need code to recognize swap signatures,
similar to what we do for ext2 in (gnu build file-systems).
For #3, what about changing the ‘target’ field of ‘mapped-device’ such
that it can be a list of /dev file names?
For #2, I’m not sure we need to change anything, but let’s discuss it
later. :-)
Ludo’.
