Bug#956436: systemd-timesyncd will remove virtualbox-guest-utils

[Balint Reczey]

Hi Michael,

On Sat, Apr 11, 2020 at 9:53 PM Michael Biebl <biebl at debian.org> wrote:
>
> Am 11.04.20 um 10:02 schrieb luca:
> > Package: systemd-timesyncd
> > Version: 245.4-3
> > Severity: normal
> >
> >
> > # apt-get -V dist-upgrade
> > Reading package lists... Done
> > Building dependency tree
> > Reading state information... Done
> > Calculating upgrade... Done
> > The following packages were automatically installed and are no longer required:
> >    libnotify-bin (0.7.9-1)
> >    libqpdf26 (9.1.1-1)
> > Use 'apt autoremove' to remove them.
> > The following packages will be REMOVED:
> >    virtualbox-guest-utils (6.1.4-dfsg-4)
> >    virtualbox-guest-x11 (6.1.4-dfsg-4)
>
> Balint, I guess we should drop
> Conflicts: virtualbox-guest-utils,
>            virtualbox-guest-utils-hwe
> ?

Ah, yes, sorry, I did think about that, but forgot to propose the
solution in the MR.

IMO systemd-timesyncd should be the default time-daemon but also the
least preferred option to install, when some other installed package
can sync the time.

I think the cleanest solution would be virtualbox source building a
binary package that Conflicts/Provides/Replaces: time-daemon and sets
up time synchronisation with the host (
https://www.virtualbox.org/manual/ch09.html#changetimesync )

If this solution is not viable, then I think the second best option is
considering virtualbox-guest-utils as a time-daemon alternative:

AFAIK when virtualbox-guest-utils* is installed the guest's clock can
be considered to be synchronised to the host and hopefully
transitively to a reasonably good source, so I propose changing
systemd instead to depend on systemd-timesyncd | time-daemon |
virtualbox-guest-utils | virtualbox-guest-utils-hwe.  This solution
has the disadvantage of not being able to install systemd-timesyncd
when virtualbox-guest-utils is present, but should not sync time with
the host. IMO this is not a huge problem, since other time-daemon-s
can still be installed such as chrony, so the guest can still have
accurate time, just not with systemd-timesyncd.

Cheers,
Balint

PS: virtualbox-guest-utils is in contrib, but per #681419 it can still
be used as an alternate dependency.

-- 
Balint Reczey
Ubuntu & Debian Developer