[systemd-devel] howto migrate some things to systemd

[Michael Olbrich]

On Wed, Apr 20, 2011 at 01:21:06AM +0200, Lennart Poettering wrote:
> On Sun, 17.04.11 10:33, Michael Olbrich (m.olbrich at pengutronix.de) wrote:
> > I'm trying to migrate some stuff to systemd, but I have some problems
> > getting it right.
> > The scenario:
> > I'm cross-building root file systems. I try to do as much as possible
> > on the host system, but there is some stuff that needs to run on the target
> > when booting for the first time. I'm not sure how to integrate this with
> > systemd.
> > Some of the issues I have:
> > - With a classic init, the init-script just touches a file to indicate the
> >   one-time stuff is complete. Is there a better way for this with
> >   systemd?
> 
> You could do this too, and then use ConditionFileExists=/flagfile to
> suppress execution of the service. 

That's exactly what I'm looking for.

> If this is for SSH keys and stuff you might even want to split this up
> into several units and just look for the sshd key files
> directly. i.e. stick in your ssh-keygen.service something like this:
> 
> ConditionFileExists=!/etc/ssh/ssh_host_rsa_key
> 
> That way are things are nice and robust. And it comes at the cost of an
> access() syscall. Which I think is pretty cheap.

Hmmm, If I do this then all such tasks would be triggered at the same time,
right? In contrast to the usual startup tasks this stuff is rather resource
intensive. Is there a way to serialize this?

Regards,
Michael Olbrich

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