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

Rob nomail at example.com
Thu Sep 19 16:20:26 UTC 2013

Horvath Bob-BHORVAT1 <Bob.Horvath at motorolasolutions.com> wrote:
>> Please read the knowledge base article on the VMware site for a full
>> explanation of how it works and what you can configure.
> I think the confusing aspect to many is that the recommendations from VMware are to run NTP on the guests to get time from an accurate time source, but not how to provide accurate time to VMs. 
> I think the OP is saying that what they used as their stratum "x" time source just got virtualized.  So what works then? 
> 1) Having the guests pointed to where the newly virtualized ntp server points now?  
> 2) Having ntpd running somewhere on real iron.
> For 1), the reason they may have had a stratum "x" server in the first place is because they can't directly use or don't want to hammer the "x-1" server. 
> For 2), they just virtualized what used to be bare iron.  Their only option left is to put it on the ESXi bare iron. 

What we have is a similar situation, we had a physical machine providing
ntp service to the network and we went to virtualisation.

The machine still providers good time.  It is still synchronized to
time sources on the network as it was before, and it still provides time
to other servers and clients on the local network.  Servers are other
virtual servers on the same ESX hosts.  Loading of the origin time
servers is the same.

The only difficulty is that when you set this same server as the NTP
source in ESX, it won't be accessible during boot.  Similar problem
exists for DNS server, when it is virtualized.

As we have two locations, we provide the DNS and NTP servers of the
second location as alternatives.  And hope they won't have to boot

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