[CentOS] NTP and hardware clock

Wed Oct 11 17:57:48 UTC 2006
Grant McChesney <grantmc at gmail.com>

On 10/11/06, Dag Wieers <dag at wieers.com> wrote:
> Hi,
> I had the following problem today. Because of a misconfigured
> network switch one system suddenly didn't have any network.
> After a reboot (with the network still unavailable) NTPD refused to start.
> Most likely because the initial ntpdate failed to work. I find this
> troubling, because when the network was restored, NTPD could have resumed
> working (like I'd expect from a true daemon).

I too have similar complaints with NTPD on CentOS 3.  If any of my
CentOS 3 servers lose power, NTPD refuses to start on next boot.  If I
check the status on the ntpd process, it says process is dead but pid
file exists.  Server time changes to hwclock, which is usually off 1
hour thanks to daylight savings.  Interestingly enough I have never
had the problem on a CentOS 4 server.

> Now, what was more peculiar was that the hardware clock was completely
> off. I also had assumed that somehow the hardware clock was kept in sync,
> but now after rebooting without network, the system clock was skewed.
> Is there some way to:
>  + Make ntpd run, even when no ntp-server could be contacted
>  + Make ntpd synchronise the hardware clock automatically
> PS Yes, I know I can run ntpdate from cron or run hwclock to synchronize
> my hardware clock. But shouldn't this be part of the infrastructure
> (either ntpd or the initscripts) ?

That would be a nice feature in the initscript.  I've settled for the
cron fix for now to keep my hwclock in sync.