[Pool] Leap second at end of June 2015

Martin Burnicki martin.burnicki at meinberg.de
Tue Jan 6 08:42:59 UTC 2015

Miroslav Lichvar wrote:
> There is one already there, sort of. Leap seconds are included in the
> "right" timezones from the tzdata package. If you use a distribution
> that updates the tzdata package regularly and keep your system up to
> date, the information about an upcoming leap second should be included
> in the timezones before it actually happens.
> chrony can be configured to use this by adding "leapsectz right/UTC"
> to chrony.conf. Restart is not necessary when tzdata is updated, it
> will be reloaded automatically.
> However, this is not equivalent to having the NIST leapseconds file as
> the expiration date is lost, the applications can't tell if there
> really is no leap second in a given month or that the timezone just
> wasn't updated yet.

There has been a discussion about this on the tzdist mailing list. See 
this thread:

I have proposed to use the IERS file as authoritative source, since the 
NIST file doesn't seem to be accessible from all over the world. See 
David Taylor's post on this list some hours ago.

The IERS file now also provides an expiration date, and the maintainer 
of the TZ data base, Paul Eggert, has mentioned that he has added some 
code which now provides the expiration date in the TZ DB leapsecond file:

However, I haven't tried this and I'm not sure which changes are 
required in some libraries or applications to *evaluate* the expiration 

Current versions of ntpd should handle the expiration date, however the 
one provided by the NIST-style file.

Martin Burnicki

Senior Software Engineer

MEINBERG Funkuhren GmbH & Co. KG
Email: martin.burnicki at meinberg.de
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