Erroneous Leap Second Introduced at 2014-06-30 23:59:59 UTC

Tim Heckman t at heckman.io
Wed Jul 2 02:19:37 UTC 2014


On Tue, Jul 1, 2014 at 12:35 PM, Majdi S. Abbas <msa at latt.net> wrote:
> On Tue, Jul 01, 2014 at 12:20:12PM -0700, Tim Heckman wrote:
>> Our systems all have loopstats and peerstats logging enabled. I have
>> those log files available if interested. However, when I searched over
>> the files I wasn't able to find anything that seemed to indicate this
>> was the peer who told the system to introduce a leap second. That
>> said, I might just not know what to look for in the logs.
>
>         Look at the status word in peerstats; if the high bit is
> set, that's your huckleberry.
>
>         See: http://www.eecis.udel.edu/~mills/ntp/html/decode.html

I've taken a look at all of the peerstats available for this host, and
surprisingly none of them are showing code 09 (leap_armed). I'm also
fairly certain that I know when some of my systems armed the leap
second (within a 60-120s window) based on our monitoring. Around those
times everything seems normal according to peerstats. Looking at

I am running Ubuntu 10.04 on this box, which is ntp v4.2.4p8. I'll
need to looking to see if the printing of this flag was added later;
otherwise, it would seem some of my systems picked up a phantom leap
second from an unknown source with one of them actually executing it.

Thanks for the decoder ring. My Google-fu wasn't hitting the right keywords.

>> Correct, I was hoping to determine which peer it was so I can reach
>> out to them to make sure this doesn't bleed in to the pool at the end
>> of the year. I was also more-or-less curious how wide-spread of an
>> issue this was, but I'm starting to think I may have been the only
>> person to catch it in the act. :)
>
>         You might want to upgrade to current 4.2.7 development code,
> wherein a majority rule is used to qualify the leap indicator.

We're going to be doing some system refreshes coming soon, so that may
be something we'll need to look at. I didn't realize this was
happening as part of the 4.2.7 development branch. Definitely an
interesting feature, especially after this. :p

>         Cheers,
>
>         --msa

Thanks again, Majdi.

Cheers!
-Tim


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