[systemd-devel] How to run *ctl command using systemd-nspawn

[Koen Kooi]

Op 17 apr. 2013, om 17:20 heeft Lennart Poettering <lennart at poettering.net> het volgende geschreven:

> On Wed, 17.04.13 17:09, Lennart Poettering (lennart at poettering.net) wrote:
> 
>> 
>> On Tue, 16.04.13 09:11, Koen Kooi (koen at dominion.thruhere.net) wrote:
>> 
>>> Hi,
>>> 
>>> To help with flashing the onboard eMMC of a 100000 boards I'm using systemd-nspawn to run package postinstall scripts that generate UUIDs and some other things and it's working great for that! Every board now has a unique value in /etc/machine-id instead it being empty and systemd randomizing it on startup.
>>> 
>>> What doesn't work however is something like this:
>>> 
>>> 	systemd-nspawn -D ${PART2MOUNT} /usr/bin/timedatectl set-timezone Europe/Paris
>>> 
>>> or this:
>>> 
>>> 	systemd-nspawn -D ${PART2MOUNT} /usr/bin/hostnamectl set-hostname BeagleBoneBlack
>>> 
>>> I know I can run the lowlevel 'ln -sf <zoneinfo> /etc/timezone' or echo the name into /etc/hostname, but I'd like to use the *ctl commands because they work and have error handling built-in. 
>>> it looks like I would need -b to get the *ctl commands to work, but -b
>>> doesn't support running single commands and exiting.
>> 
>> timedatectl is just a frontend to timedated. So, without running
>> timedated inside of the container this is not going to be easy to do.
> 
> Ah, I missed that you'd actually be OK with booting up the whole thing
> for this command... You'd just need a nice way to run something after
> boot-up is complete, and that immeidately shuts down the container
> afterwards, right?

Exactly!

> Hmm, here's an idea:
> 
> we could add a generator to systemd which looks for "systemd.run=" or so
> on the kernel cmdline and simply generates throw-away unit files from
> that, that runs the specified command(s) and triggers a shutdown
> afterwards... Would that work for you?
> 
> i.e. you'd then call:
> 
> systemd-nspawn -bD /srv/foobar \
>               systemd.run='/usr/bin/timedatectl set-timezone Europe/Paris' \
>               systemd.run='/usr/bin/timedatectl set-hostname BeagleBoneBlack'
> 
> and so on...
> 
> I think that would be reasonably pretty?

And it totally works for my usecase as well!

regards,

Koen