[CentOS] timekeeping on VMware guests

Brian Mathis brian.mathis at gmail.com
Wed Oct 14 17:57:32 UTC 2009


On Wed, Oct 14, 2009 at 1:38 PM, James A. Peltier <jpeltier at fas.sfu.ca> wrote:
> On Tue, 13 Oct 2009, Carlos Santana wrote:
>
>> Howdy,
>>
>> I am having time-drift issues on my CentOS VM. I had referred to
>> following documentation:
>
> The issue I had with time drift was due to running NTP inside the VM.
> Don't do it.  The VM should get it's time through the VMWare tools that
> are installed on the guest.  Once I did this the drift disappeared.
>
> --
> James A. Peltier


I recently wrote a script that retrieves the current time from an NTP
server and compares it to the local time.  You may be surprised to
know that inside of a VM the time is constantly drifting, and when it
gets to 60 seconds difference, it is forcibly reset by vmware tools.
In other words, this is a bad way to handle time.

As has been already mentioned, the timekeeping best practices from
vmware have changed from using vmware tools to using NTP and correct
kernel options (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427).
 I have not yet implemented this myself, but it seems like a better
way to handle it.



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