CentOS use Xen virtual machine NTP time cannot sync problem

The local clock in the Xen Linux machine is by default (done) synchronized with the physical host clock, in order to change the time it uses the Sync Service for NTP, the kernel parameters must be set by the virtual machine:
Shell Code
Echo 1 >/proc/sys/xen/independent_wallclock

The/etc/sysctl.conf configuration file in the virtual machine adds the following two and takes effect after reboot.
Config code
# Set Independent Wall clock time
Xen.independent_wallclock=1

If you do not want to restart the virtual machine for immediate effect, use the following command:
Shell Code
Sysctl-p