[Pool] Leap second at end of June 2015

Daniel Frank ntp at tokuko.de
Thu Jan 8 17:15:26 UTC 2015


Am Donnerstag, 8. Januar 2015, 12:50:04 schrieb Max Grobecker:
> Hi,
> just for me to clarify:
> What am I supposed to do as a pool server maintainer?
> Should I be fine after updating tzdata on my system (Ubuntu 10.04 LTS) or do
> I have to load any files and tell ntpd to use them?
> I'm a bit confused now ;-)

I think it's rather simple for many of the pool server admins.
Are you running a stratum 1 server (i.e. you have your own hardware clock, GPS 
receiver, DCF77 or similar)?
If not, you're save, your ntpd should pick up the announcement of the leap 
second from your upstream servers without you doing anything. Only works if 
those upstream servers are maintained properly, of course.
It might be worth to have a look on the output of June 30th in the late 
afternoon and see if there are some servers that seem to be off by a second 
(or maybe check right after midnight on first of July? don't know for sure). 
If that happens, you may have server admins there that do not care about leap 
second announcement. If you care aobut that, you should probably figure out 
which ones are wrong and remove them from your upstream servers. If you use 
official servers like the PTB in germany and many universities as upstream 
servers you probably don't have to worry, they will likely get it right. Even 
if less than half of them get it wrong, ntpd will decide that it also has to 
announce the leap second.

If you have your own hardware clock, I believe it depends on the type of 
receiver. Some may be able to inform ntpd of the leap second, some may not. So 
if you're a stratum 1 server, you should investigate.
Or accept that you're a falseticker for a couple of hours as Rob suggested.

Problem with falsetickers is that ntpd does not know who's wrong if half of 
its upstream servers say it's midnight and the other half says it's one second 
before midnight... So if there are just a couple of falsetickers in the pool 
that's not an issue.
If there are many though, it becomes an issue.

Many people do not care about a one second time difference, but there will be 
some that do care and being a falseticker makes it harder for them.

Target of the pool is to provide the correct time with an error of less than 
0,1 seconds (=100ms), so being off by one second is a noteable error and will 
get you temporarily kicked out of the pool while you're providing the wrong 
As soon as your server has gotten its own time back to correct time, it will 
automatically be included again after it has earned enough points again.


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