Continued from opensuse-factory:
Probably other virtualization technology have the same issue, do not use ntp. I do not know for certain.
With xen, my guests run ntpd and have xen.independent_wallclock=1.
And both host and guest try to adjust the speed of the mother board hardware clock chip? (not the bios clock, that's a very different one).
No, only the Dom0 does that. The guests are independent when you use xen.independent_wallclock=1.
http://www.novell.com/documentation/vmserver/config_options/data/b9qzhq5.htm...
But if you run the ntp daemon on guests, it tries to adjust the speed of the clock there. That's how it works.
Of course, that's what you want it to do. You want the guest clock synchronized. It would appear to be a good idea to have ntp on the xen Dom0 govern the clock for all the guests, but in my experience systemd does not like that. I looked into in March 2015 when I was virtualising some systems, and found the Novell page above. The Xen FAQ: https://wiki.xen.org/wiki/Xen_FAQ_DomU also recommends running ntp in each DomU. Finally, Werner Flamme wrote:
When you install SAP systems on top of Xenified VMs, there is the recommendation to do the latter: disable the sync and run a separate ntpd in the DomU. This is also a recommendation for VMs inside a VMWare environment - the problem ist the same there.
Back in March last year I did ask what the typical practice was, but noone had any suggestions. -- Per Jessen, Zürich (25.2°C) http://www.dns24.ch/ - free dynamic DNS, made in Switzerland. -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org