[Pool] Leap second is coming

lst_hoe02 at 79365-rhs.de lst_hoe02 at 79365-rhs.de
Wed Apr 15 14:29:18 UTC 2015


Zitat von Martin Burnicki <martin.burnicki at meinberg.de>:

> Kiss Gábor wrote:
>> Hi guys,
>>
>> I just remind you there will be a leap second at the end of June.
>> All of us should prepare of ntp pool servers as described here:
>> http://lists.ntp.org/pipermail/questions/2008-August/019336.html
>
> While it's generally a good idea to use a leap second file, the  
> hints in the 2nd part of the referred email should be more  
> appropriate for current installations running ntpd 4.2.6 or 4.2.8,  
> i.e., use the "leapfile" keyword in ntp.conf.
>
> Please note that if you run 4.2.6 with an outdated leap second file  
> your NTP server will *not* accept any leap second warning from  
> upstream servers or a refclock.
>
> This is *not* a bug but the intended behavior. See NTP bug 861,  
> comment 46 and 47, as well as the following discussion:
> http://bugs.ntp.org/show_bug.cgi?id=861#c46
>
> So if you are running ntpd 4.2.6 with a leap second file configured  
> then please make sure to use the current version of the leap second  
> file. Otherwise you *will* encounter a problem when the leap second  
> occurs.
>
> BTW, in 4.2.8 this has fortunately been reworked, so an expired leap  
> second file is ignored as it ought to be, and leap second  
> announcements from other sources are accepted if the leap second  
> file has expired.
>
> Martin
> -- 
> Martin Burnicki
>
> Senior Software Engineer
>
> MEINBERG Funkuhren GmbH & Co. KG
> Email: martin.burnicki at meinberg.de
> Phone: +49 (0)5281 9309-14
> Fax: +49 (0)5281 9309-30

Sorry for maybe asking the obvious but

- How to check if ntp is configured with a leap second file? Must it  
be listed in ntp.conf or is there some default set?

- Without a leap second file ntp will simply decide based on the  
majority of upstream ntp servers it it will pass the information or  
will it pass the information from the "*" upstream?

- What is the expected timeframe of leap second file changes  
(Month/Years/Decade)??

What happens if the upstream get it wrong and omit the leap second?  
Are we wrong by one second or do we simply switch later and slower?

Thanks for explainig it to mortals ;-)

Andreas




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