[CentOS] ntpd date sync before service startup

Thu May 15 22:55:08 UTC 2008
John R Pierce <pierce at hogranch.com>

David Hláčik wrote:
> Hello,
> in system-config-date i have checkbox synchronize date before service 
> startup.
> Which config switch,file does it affect? I want to turn it on on my 
> CentOS machine without xauth , just editing config files , i was 
> hoping it could be in /etc/sysconfig/ntpd but no.

most likely, the system-config util is setting that option in 
/etc/sysconfig/ntpd which by default reads...

# Drop root to id 'ntp:ntp' by default.
OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid"

# Set to 'yes' to sync hw clock after successful ntpdate

# Additional options for ntpdate

if -x is /not/ set in OPTIONS, it calls /usr/sbin/ntpdate with various 
parameters, this hard sets the system time to the NTP server time. if -x 
/is/ set, it does the time step thing

if SYNC_HWCLOCK=yes, then it invokes sync_hwclock in the 
/etc/init.d/ntpd script, which in turn runs /sbin/hwclock with various 
options as specified.