[CentOS] timekeeping on VMware guests

Ray Van Dolson rayvd at bludgeon.org
Wed Oct 14 18:04:37 UTC 2009


On Wed, Oct 14, 2009 at 10:55:40AM -0500, Carlos Santana wrote:
> Following steps were taken to set up my CentOS VM guest (without
> vmware-tools installed):
> 
> 1. Kernel options added as:
> divider=10
> clocksource=acpi_pm
> 
> 2. ntp.conf file was modified as per wiki instructions as follows:
> (add to the top of the file)
> # modification as per http://kb.vmware.com/kb/1006427
> # The configuration directive tinker panic 0 instructs NTP not to give up
> # if it sees a large jump in time and must be at the top of the ntp.conf file.
> tinker panic 0
> # end of mod
> 
> (comment out 2 lines as below)
> # modification as per http://kb.vmware.com/kb/1006427
> # It is also important not to use the local clock as a time source,
> # often referred to as the Undisciplined Local Clock. NTP has a
> # tendency to fall back to this in preference to the remote servers
> # The following 2 lines commented out.
> 
> # when there is a large amount of time drift.
> # server        127.127.1.0     # local clock
> # fudge 127.127.1.0 stratum 10
> 
> 3. Create /etc/ntp/step-tickers and add these lines:
> 0.centos.pool.ntp.org
> 1.centos.pool.ntp.org
> ----------------------
> 
> Any missing pointers..?
> 

Looks good to me.  The only issue might be if you have a firewall
blocking access to the given NTP servers.

What kind of symptoms are you seeing after doin the above, rebooting,
sync'ing the time, then leaving ntpd doing it's thing?

Does the clock start going too fast?  Too slow?  Do you see any errors
in dmesg or /var/log/messages?

Ray


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