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

[Martin Pitt]

Josh Triplett [2015-02-16 21:49 -0800]:
> > Note that openntpd and chrony both have a Provides: time-daemon, but
> > ntp doesn't.
> 
> Interesting.  Any idea why?

No, I don't; probably just an omission. openntpd and chrony both have
an explicit Conflicts: ntp, though.

> > 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?

That's certainly the idea, yes. The Alias= mechanism works a bit
differently than Provides: on a packaging level; e. g. it must be
possible to have several of them installed in parallel. So AFAIK
packages which use this schema need to either systemctl disable
<aliasname> first (if they want to set itself as the "selected
alternative") or not enable itself at all (if they are not the
"selected alternative").

> > 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?

I wish we could. But don't forget that we still have to support at
least SysVinit and perpaps even more (openrc? upstart?). As long as we
have those, we probably have to keep these uber-complex mechanisms
like systemd-default-display-manager-generator which sync these
config files with the systemd unit enablement.

Martin

-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)