XEN - Time handling in Linux VMs (Problemas con NTP y XEN)

Problemas con la hora de las maquinas virtuales? Una forma de solucionarlo es hacer que el DomU sea independiente de la hora de su Dom0 de la siguiente manera.

Para probarlo
echo 1 > /proc/sys/xen/independent_wallclock

Para que sea definitivo
en /etc/sysctl.conf

# Set independent wall clock time
xen.independent_wallclock=1

Manera alternativa.
The independent_wallclock=1 may also be passed as a boot parameter to the VM.

http://docs.vmd.citrix.com/XenServer/4.0.1/guest/ch04s06.html

By default, the clocks in a Linux VM are synchronized to the clock running on the control domain, and cannot be independently changed. This mode is a convenient default, since only the control domain needs to be running the NTP service to keep accurate time across all VMs. Upon installation of a new Linux VM, make sure you change the time-zone from the default UTC to your local value (see Section 4.8, “Release Notes” for specific distribution instructions).

The ntpdate program is deprecated

The ntpdate program is deprecated and should not be used any more. To
quote the upstream ntp developers:

"The functionality ntpdate offered is now provided by the ntpd daemon
itself. If you call ntpd with the command line option -q it will
retrieve the current time and set it accordingly."

Please check the Network Time Protocol (NTP) daemon man page and
http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate
for further information.

You can replace the ntpdate call with "rcntp ntptimeset" to achieve an
inital poll of the servers specified in /etc/ntp.conf.

The program /usr/sbin/sntp offers comparable functionality to ntpdate.
Specifically
sntp -P no -r pool.ntp.org
is equivalent to
ntpdate pool.ntp.org

For further details please refer to the man page of sntp.


sntp -P no -r ntp.dominio.com