[vdsm] vdsm hosts clock sync

[Shahar Havivi]

Hi,

I want to add a new feature that reports migration actual downtime (the time
that the VM was inaccessible to the user).

Libvirt reports that information but the vdsm hosts need to be in sync by clock
time.
I can measure the ping for NTP server an report back to the user if the ping
is too long (more then ~100ms or so) - a way to do that is via ntpstat shell
command.
The NTP delay can be report back via vdsStats and can be performed every
few hours or so.

Anyone knows of a better way that we can sync between hosts?

Thank you,
  Shahar Havivi.