[ntp:questions] Synchronizing contrived time

William Unruh unruh at invalid.ca
Tue Mar 11 18:34:41 UTC 2014


On 2014-03-11, Amit Dor-Shifer <amit.dor.shifer at gmail.com> wrote:
> Hi.
>
> With the configuration I've been advised here, I'm still not able to
> maintaine a skewed time on the server. ntpd does execute, yet a few seconds
> after its initialization, it resets the time skew I've generated (I.E, even
> b4 the client had a chance to query it)

??? It has nothing to "reset" with respect to. why do you not post your
whole ntp.conf file here for the server?


>
> $ sudo tail -f /var/log/messages
> #...snip
> $
> $
> $ date
> Tue Mar 11 20:43:03 EST 2014
> $ cat ~/test_ntpd/ntp.conf
> server 127.127.1.0 minpoll 4 maxpoll 4
> $ sudo date -s "$(date) - 50 minute"
> Tue Mar 11 19:53:30 EST 2014
> $ date
> Tue Mar 11 19:53:35 EST 2014
> $ sudo ntpd -g -f ~/test_ntpd/ntp.conf
> sudo: timestamp too far in the future: Mar 11 20:43:30 2014
>
> Mar 11 19:54:06  ntpd[31080]: ntpd 4.2.6p5 at 1.2349-o Sat Nov 23 18:21:48 UTC
> 2013 (1)
> $ Mar 11 19:54:06  ntpd[31081]: proto: precision = 1.495 usec
> Mar 11 19:54:06  ntpd[31081]: 0.0.0.0 c01d 0d kern kernel time sync enabled
> Mar 11 19:54:06  ntpd[31081]: format error frequency file
> /home/amit/test_ntpd/ntp.conf
> Mar 11 19:54:06  ntpd[31081]: Listen and drop on 0 v4wildcard 0.0.0.0 UDP
> 123
> Mar 11 19:54:06  ntpd[31081]: Listen and drop on 1 v6wildcard :: UDP 123
> Mar 11 19:54:06  ntpd[31081]: Listen normally on 2 lo 127.0.0.1 UDP 123
> Mar 11 19:54:06  ntpd[31081]: Listen normally on 3 eth0 10.250.129.79 UDP
> 123
> Mar 11 19:54:06  ntpd[31081]: Listen normally on 4 lo ::1 UDP 123
> #...snip
> Mar 11 19:54:06  ntpd[31081]: peers refreshed
> Mar 11 19:54:06  ntpd[31081]: Listening on routing socket on fd #22 for
> interface updates
>
> $
> $
> $
> $ date
> Tue Mar 11 19:54:09 EST 2014
> $
> $
> $
> $
> $ Mar 11 19:54:16  ntpd[31081]: 0.0.0.0 c016 06 restart
> Mar 11 19:54:16  ntpd[31081]: 0.0.0.0 c012 02 freq_set kernel -25.992 PPM
>
> $
> $ date
> Tue Mar 11 19:54:21 EST 2014
> $ Mar 11 20:44:23  ntpd[31081]: 0.0.0.0 c61c 0c clock_step +3000.023162 s
> Mar 11 20:44:23  ntpd[31081]: 0.0.0.0 c614 04 freq_mode
> Mar 11 20:44:24  ntpd[31081]: 0.0.0.0 c618 08 no_sys_peer
>
> $
> $
> $
> $ date
> Tue Mar 11 20:44:29 EST 2014
>
> David, when you were suggesting before that I didn't configure the correct
> local clock driver - is that achieved via ntp.conf? Could you refer me to
> an example?
> Thanks
>
>
> On Tue, Mar 11, 2014 at 6:12 AM, William Unruh <unruh at invalid.ca> wrote:
>
>> On 2014-03-10, Amit Dor-Shifer <amit.dor.shifer at gmail.com> wrote:
>> > Thanks.
>> > Would this then be the reference implementation?
>> >
>> > [user at centos test_ntpd]$ rpm -qf $(which ntpd)
>> > ntp-4.2.6p5-1.el6.centos.x86_64
>> > [user at centos test_ntpd]$ cat ~/test_ntpd/ntp.conf
>> > server 127.127.1.0 minpoll 4 maxpoll 4
>> > [user at centos test_ntpd]$ ps -ef|grep ntp
>> > user     13411 12236  0 22:03 pts/0    00:00:00 grep ntp
>> >
>> > # moving clock back some 50 mins
>>
>> AAAAAARGH. No do not do that. ntpd is horrible at handlking sudden
>> changes in time. It is like testing how good a car is by driving it off
>> a cliff. It was never designed to fly.
>>
>>
>> >
>>
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>>



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