Re: Q: "dn: cn=Uptime, cn=Time, cn=Monitor" non-monotonic occasionally?

To: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>

Subject: Re: Q: "dn: cn=Uptime, cn=Time, cn=Monitor" non-monotonic occasionally?

From: "Brett @Google" <brett.maxfield@gmail.com>

Date: Fri, 29 Apr 2016 19:50:34 +1000

Cc: openldap-technical <openldap-technical@openldap.org>

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On Thu, Apr 28, 2016 at 6:48 PM, Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> wrote:

Hi!

I'm running a NRPE monitor that monitors openLDAP. To compute delta values, the NRPE plugin stores the "dn: cn=Uptime,cn=Time,cn=Monitor" reported by openLDAP to compare it with the current value (to build the time difference). If the time difference is negative, the plugin reports a "server restart" event.

So far, so good...

However, very rarely (once every few weeks) a false server restart is reported. Viewing the historic logs, I can only assume that openLDAP reports a bad uptime value now and then. Could this be?

If uptime is a calculation based on the system clock, is there some process such as ntpd or vmware tools, periodically updating the system clock, sometimes backwards ?

If so, maybe look for an option to limit backwards updates.

Cheers

Brett