Bug#755722: systemd must sync systemclock to RTC on shutdown

[Josh Triplett]

On Tue, Feb 17, 2015 at 06:44:28AM +0100, Martin Pitt wrote:
> Josh Triplett [2015-02-16 17:37 -0800]:
> > Seems like systemd could take a lesson from Debian packaging metadata
> > here.  Every mail transport agent, rather than conflicting with every
> > other, has a "Provides: mail-transport-agent" and "Conflicts:
> > mail-transport-agent", specifically because they all want to provide
> > /usr/sbin/sendmail and (usually) listen on port 25.
> 
> Note that openntpd and chrony both have a Provides: time-daemon, but
> ntp doesn't.

Interesting.  Any idea why?

> > Unit files could do something similar, if systemd had an appropriate
> > "virtual service" mechanism.
> 
> It does, it's called "Alias=" (man systemd.unit).

Can Alias work together with Conflicts on that alias, such that each of
several services all Alias a given virtual service and Conflicts with
other providers of that service?  If so, what about using that for
systemd-timesyncd and all of the other time services, at least once they
all have native service files?

> We use it for display-manager already (kind of, as we also have to
> support the old /etc/X11/default-display-manager config file).

Also, post-jessie, do you have any plans to do a one-time migration away
from that display manager configuration file, similar to the various
one-time migrations away from sysvinit-specific config files like
/etc/default/rcS?

- Josh Triplett