systemd-fsck at .service

[Dimitri John Ledkov]

On 2 December 2015 at 13:14, Colin Watson <cjwatson at ubuntu.com> wrote:
> On Mon, Nov 30, 2015 at 05:29:35PM +0200, Tom H wrote:
>> 1) How does the unit now what "%f" is?
>
> See the "SPECIFIERS" section of the systemd.unit(5) manual page.
>
>> 2) "%i" is, in the case that I set up a few weeks ago,
>> "sys-devices-pci0000:00-0000:00:0d.0-ata4-host3-target3:0:0-3:0:0:0-block-sdb-sdb1".
>> Should it have "sdb" in it since it's supposed to be an unstable name?
>
> There doesn't seem any particular reason for the various %i.device units
> that this particular service is bound to to need stable names.  The
> purpose of systemd-fsck at .service is just to run fsck on all your block
> devices; it doesn't much matter what they're called.
>
> Jobs that need to run on only particular block devices would typically
> be udev rules rather than systemd units, I think; but if need be a
> systemd unit could always use udevadm to inspect the udev database for
> information about a particular device.  (There may be some better way.)
>

udev rules can add magic variables to trigger systemd units. Thus e.g.
leave a systemd unit inert and use udev rules to add systemd_wants=
variables et.al. see
http://www.freedesktop.org/software/systemd/man/systemd.device.html

-- 
Regards,

Dimitri.