[ntp:questions] question regarding NTP configuration for clusters, and "cluster time" stability

rotordyn@yahoo.com rotordyn1 at gmail.com
Wed Sep 30 04:14:31 UTC 2009

> Well, have 4 of them be the internal top level, and have the rest of the
> nodes use all 4 as their servers. Then make sure that if one looses
> sync with UTC, it drops down in stratum so that the rest of the machines
> will ignore it.

That seems logical. I'll look into that, thank you.

> >I can do that too, but I run into chicken and egg issues, in that the
> >cluster software needs the nodes to be in synch before starting,
> >so NTP must already be running.
> Uh, yes, the computer must run in  order for the computer clock to run.
> That is Always true.

That's not quite what I was saying. I have clustering software that
has modest time synchronization requirements, in that all nodes'
clocks in the cluster need to be within a second of each other.
In the current implementation, the software will not start unless
ntpd is running. I could add functionality to that software to
modify ntpd configurations dynamically, based on cluster state.
But since ntpd must be running prior to the cluster software
starting, at a minimum I need to have a boot-strap configuration
that allows ntpd to start up and function at least as well as it
does in the current implementation, even if the config might be
changed in response to a change in cluster state.

> Well, yes, but then lines run through the roof or a window are usually
> pretty easy.

Adding hardware is not viable. Besides which, it really is a fairly
modest requirement of time accuracy, which shouldn't require
special hardware.


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