[ntp:questions] ntpd -qg sleeping processes

unruh unruh at wormhole.physics.ubc.ca
Fri Dec 31 17:36:30 UTC 2010

On 2010-12-31, RICCARDO <ric.castellani at alice.it> wrote:
> On 31 Dic, 15:49, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
>> RICCARDO wrote:
>> > I scheduled process in crontab on all machines:
>> > 00 05 * * * /usr/sbin/ntpd -qg
>> > I can't understand where it was problem because if now I run ntpd -qg
>> > I works fine.
>> > But there is timeout fot ntpd ? I have no logs for this date !
>> > What do you think ?
>> I think that running ntpd from cron every night as a replacement for
>> ntpdate is pretty stupid. :-(
>> I assume you have a very good reason for why you cannot simply let ntpd
>> run normally?
>> Terje
>> --
>> - <Terje.Mathisen at tmsw.no>
>> "almost all programming can be viewed as an exercise in caching"
> man of ntpd suggests to run ntpd -qg in client

ntpdate is deprecated and is due (well was due 5 years ago or so) to
disappear "soon". ntpd -qg is suggested as the replacement

man ntpd

In  some  cases it may not be practical for ntpd to run continuously. A
common workaround has been to run the ntpdate program from a cron  job
at  designated  times.  However, this program does not have the crafted
signal processing, error checking and mitigation  algorithms  of ntpd.
The  -q  option  is intended for this purpose. Setting this option will
cause ntpd to exit just after setting the clock for the first time. The
procedure  for initially setting the clock is the same as in continuous
mode; most applications will probably want to specify the  iburst key-
word  with the server configuration command. With this keyword a volley
of messages are exchanged to groom the data and the  clock  is set  in
about  10  s. If nothing is heard after a couple of minutes, the daemon
times out and exits. After a suitable period of mourning,  the ntpdate
program may be retired.

Clearly the mourning period is pretty long.

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