Richard DEMONGEOT wrote: > Dear all; > > I'm working to prevent leap second impact on some infra structure, and > i'll try to make a test. > > As i can see on the documentation page of NTP (1), leap second raise a > warning 28 days before the leap second, and insert a linux kernel flag > 23 hours before.
No. Current versions of ntpd only send the leap second warning flag on the last day before the leap second occurs. Even if you send a query to a remote ntpd which would send a leap second warning days in advance the daemon can only send a leap second if it is aware of an upcoming leap second, i.e. if the daemon itself has received a leap second announcement from a refclock, or the operator has already provided it with a *current* leap second file. *If* the server operator hasn't restricted remote monitoring you can run the command "ntpq -c rv" against a machine which prints some information, e.g.: associd=0 status=0415 leap_none, sync_uhf_radio, 1 event, clock_sync, version="ntpd [email protected] Wed Oct 19 10:10:04 UTC 2016 (1)", processor="x86_64", system="Linux/3.16.7-45-desktop", leap=00, stratum=1, precision=-23, rootdelay=0.000, rootdisp=1.060, refid=shm0, reftime=dbc711a6.10f31e48 Fri, Nov 4 2016 14:54:46.066, clock=dbc711ab.019d4889 Fri, Nov 4 2016 14:54:51.006, peer=7906, tc=4, mintc=3, offset=-0.003182, frequency=-8.160, sys_jitter=0.000000, clk_jitter=0.000, clk_wander=0.001, tai=36, leapsec=201701010000, expire=201706280000 In the example above the parameter "leapsec=201701010000" tells that the daemon is aware of the upcoming leap second, so it will start to send the announcement flags to its kernel and its clients appropriately, about 24 hours before the leap second occurs. > However, i don't see on the RFC (rfc5905) such information about > warning. The LI flag is a two bit flag, with following values : > | 0 | no warning | > | 1 | last minute of the day has 61 seconds | > | 2 | last minute of the day has 59 seconds | > | 3 | unknown (clock unsynchronized) | > Right, and while the leap second announcement is sent out to the clients the 2 bits should read '01' instead of '00'. Martin _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
