Leap Second

[Garrett Wollman]

<<On Thu, 2 Jul 2015 06:27:28 +1000, Peter Jeremy <peter at rulingia.com> said:

> ntpd(8) has provision for specifying a leapsecond file which presumably
> makes it leap-second aware.  I haven't looked into the details.

The current NTP protocol, as implemented by ntpd, distributes
leap-second information if provided.  This information may be provided
by higher-stratum (upstream) NTP servers, or by using the "leapfile"
configuration statement in ntp.conf to specify a local copy of the
leapseconds file in NIST/USNO format.  No such file is provided by
default.  We could easily do so, but shouldn't, because that file
would take precedence over the leap indicator learned from
higher-stratum servers, and that's not desirable for clients.

If you're running a bunch of servers, you should distribute and
install the leapseconds file using your configuration-management
system.  (For example, my puppet module for NTP, which we use at CSAIL
for three NTP servers, does so:
<https://github.com/gwollman/puppet-ntp>.)

-GAWollman