[172698] in North American Network Operators' Group
Re: Erroneous Leap Second Introduced at 2014-06-30 23:59:59 UTC
daemon@ATHENA.MIT.EDU (Majdi S. Abbas)
Mon Jun 30 22:34:26 2014
X-Original-To: nanog@nanog.org
Date: Mon, 30 Jun 2014 22:27:27 -0400
From: "Majdi S. Abbas" <msa@latt.net>
To: Tim Heckman <t@heckman.io>
In-Reply-To: <CAB=D40imtSiNd53qh-7sDFESxYOD3-kJ8PT0Ub8WVSmLcyBz6w@mail.gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On Mon, Jun 30, 2014 at 05:33:52PM -0700, Tim Heckman wrote:
> I just was alerted to one of the systems I managed having a time skew
> greater than 100ms from NTP sources. Upon further investigation it
> seemed that the time was off by almost exactly 1 second.
>
> Looking back over our NTP monitoring, it would appear that this system
> had a large time adjust at approximately 00:00 UTC:
Okay. Do you have any logging configured (peerstats, etc?) for
ntpd?
> A few of our systems did alert early this morning, indicating they
> were going to be receiving a leap second today. However, I was unable
> to determine the exact cause for NTP believing a leap second should be
> added. And after some time a few of the systems were no longer
> indicating that a leap second would be introduced.
This can happen if a server is either passing along a leap
notification that it received, or is configured to use a leapseconds
file that is incorrect.
> This specific system is hosted in AWS US-WEST-2C and uses the
> 0.amazon.pool.ntp.org pool.
0 is just one server in the pool (whichever you draw by
rotation); is this the only server you have configured?
--msa
