Bug#780461: updates from #debian-systemd

[Petter Reinholdtsen <pere@hungry.com>]

[Wolfgang Schweer]
> After looking at this bug once again, there seem to be two issues:
>
> (1) The reported delay of (up to) 15 minutes is due to the fact that 
>     dhclient updates the hostname on the first lease renewal. (The
>     interval length between renewals seems to be a random value
>     something between 600 and 900 seconds.) Dhclient should update the
>     hostname on reboots immediately, though. Maybe systemd plays a
>     role, maybe not.

Could this be caused by dhclient running at a point during boot where
/etc/ is read-only, causing /usr/sbin/update-hostname-from-ip to exit
with an error code instead of updating the hostname?  It is my best
guess for why the hostname update wait for the first renewal.

It should be possible to confirm this by adding more error checking and
reporting, as I believe syslog messages are cached until /var/log/ is
writable.

> (2) For Profiles 'Workstation' and 'Minimal' the hook script is working
>     like stated above. 
>     But LTSP-Servers may have PROFILE="Workstation, Thin-Client-Server"
>     set in /etc/debian/edu/config. The hook script IMO fails to update 
>     the hostname cause there's no matching case entry.

Good catch.  Also, why is the sethostname() function in the
dhclient-exit-hooks.d/hostname script?  It seem to be completely
unused.  Remove it?

-- 
Happy hacking
Petter Reinholdtsen