[ntp:questions] running NTP as server only

David Woolley david at ex.djwhome.demon.invalid
Thu Aug 19 20:07:53 UTC 2010


folkert wrote:
Quoting....
> 
> Using NTP in Linux and Other Guests
>    The Network Time Protocol is usable in a virtual machine with proper

"is usable", not "works well"

> configuration of the NTP daemon. The 
>    following points are important:
>         Do not configure the virtual machine to synchronize to its own
> (virtual) hardware clock, not even as a 
>         fallback with a high stratum number. Some sample ntpd.conf files

This is telling you that the time being served will be very unstable. 
ntpd will probably compensate by ramping down the poll interval.

> contain a section specifying the local 
>         clock as a potential time server, often marked with the comment
> “undisciplined local clock.” Delete any 
>         such server specification from your ntpd.conf file.
>         Include the option tinker panic 0 at the top of your ntp.conf

This is telling you that the time may suffer wild excursions of more 
than 15 minutes!!!! I suspect this is to cover suspensions and host changes.

> file. By default, the NTP daemon 
>         sometimes panics and exits if the underlying clock appears to be
> behaving erratically. This option causes 
>         the daemon to keep running instead of panicking.
>         Follow standard best practices for NTP: Choose a set of servers
> to synchronize to that have accurate time 
>         and adequate redundancy. If you have many virtual or physical
> client machines to synchronize, set up 
>         some internal servers for them to use, so that all your clients
> are not directly accessing an external 
>         low‐stratum NTP server and overloading it with requests.
> 
> (vmware document of 2008, status of vmware 3.5)
> 




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