How to make ntpd synchronized immediately after reboot?
My application must run on a server with time synchronized. In order to do that I installed ntpd and I check the return value of ntpstat. It appears that it takes a very long time to get a zero return value from ntpstat, especially after reboot. Why does it take ntpd such a long period to get synchronized and how can I make it happen few seconds after reboot?
Answer
To synchronize ntp immediately after reboot, ntpdate has to run before ntpd.
To do this in systemd, you can run
systemctl -a | grep ntp
to see if ntpdate is enabled. To enable it is just run
systemctl enable ntpdate
For Linuxes that use lsb scripts, you can enable ntpdate via chkconfig.
chkconfig ntpdate on