[ntp:questions] R: Re: debugging strange ntp in virtual environment

Rob nomail at example.com
Fri Sep 20 08:16:09 UTC 2013

unruh <unruh at invalid.ca> wrote:
> On 2013-09-19, Rob <nomail at example.com> wrote:
>> unruh <unruh at invalid.ca> wrote:
>>> On 2013-09-19, Horvath Bob-BHORVAT1 <Bob.Horvath at motorolasolutions.com> wrote:
>>>>> -----Original Message-----
>>>>> From: questions-bounces+bob.horvath=motorolasolutions.com at lists.ntp.org
>>>>> [mailto:questions-bounces+bob.horvath=motorolasolutions.com at lists.ntp.org] On
>>>>> Behalf Of Rob
>>>>> Sent: Thursday, September 19, 2013 11:20 AM
>>>>> To: questions at lists.ntp.org
>>>>> Subject: Re: [ntp:questions] R: Re: debugging strange ntp in virtual
>>>>> environment
>>>>> Horvath Bob-BHORVAT1 <Bob.Horvath at motorolasolutions.com> wrote:
>>>>> >
>>>>> Why?
>>>>> What we have is a similar situation, we had a physical machine providing ntp
>>>>> service to the network and we went to virtualisation.
>>> Why why why would you want to do that? It is simply nuts. 
>> Because the boss wants to cut down on physical machines, as we are
>> migrating to external hosting.
> Oh well. You are having trouble. You wonder where it is coming from.
> Suggestions are made and you reject them. Fine.

I'm not having trouble at all!  You are the one that is having trouble.
The setup works perfectly and none of the effects you describe are
actually present.

>> Unruh, what we see time and time again: you as a hobbyist on your own
>> little PC at home have a completely different view on the world than the
>> corporate sysadmin has.
> OK, except I do admin a group of about 8 machines at my work.

8?  Wow!

>> You are always recommending things that just aren't practical.
>> Just as I can't get a Sure GPS board and install its antenna outside
>> the building with a long wire to the computer room, I also cannot decide
>> if we will virtualize or not.
> And I know what is practical how? You ask for help. Suggestions are made
> and it is up to you whether or not to impliment them. But, sometimes
> refusing them comes with a cost. So you will have to decide if the cost
> is worth it or not. 

I'm not asking for help.
I am criticising the help that you give to others, because it is
based on your own made-up assumptions and not on the facts.
And because you recommend things that may work in your bedroom to
people that work in office buildings and datacenters.

>> We virtualized about 30 servers into 3 boxes at one location, and 4
>> servers into another box at another location.  The footprint went from
>> a room full of equipment to 6HE in a rack.
>> Having a few hundred us less NTP accuracy is a small price to pay for
>> that.
> That is or course your decision. And whether it is a few hundred us or a
> few hundred ms, or sec will depend on how busy your virtual machines
> are. If they get busy enough, ntpd will not be able to handle the wild
> fluctuations in drift rate. 

This may be true on your copy of VMware Server running on your Linux
PeeCee, but it is not true on ESX on properly configured and dimensioned

> Why do you not have your ntp servers running on the underlying OS,
> instead of on your virtual machines?

Because that is not possible.
What people like you don't know is that the "underlying Linux OS" that
you see in an ESX installation is actually a Linux VM running on the
virtualisation kernel just like your own machines.
And using it for NTP is not optimal because it is an older version,
you would need to tinker with the firewall, and you cannot easily
attach a radio refclock if you have one.

>> If only you would understand such things...
> I do. But if only you would understand that the information you have
> given above was NOT in your original request. 

I have made no request.

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