Re: [chrony-users] Best way to force clock step at shutdown

[Hector Oron <hector.oron@xxxxxxxxx>]

Hello,

2016-01-12 17:26 GMT+01:00 Bill Unruh <unruh@xxxxxxxxxxxxxx>:
> On Tue, 12 Jan 2016, Hector Oron wrote:

>> Hello,
>>
>>  As I read on an old post here:
>>
>> http://listengine.tuxfamily.org/chrony.tuxfamily.org/chrony-users/2014/10/msg00004.html
>>
>>  The recommended way to be able to force a sync is to generate a
>> burst and wait 10 sec for measurements to complete, then do the
>> stepping on the clock.
>
>
> This is a sync of your computer's clock to the remote clock. If chrony is
> running then that will occur continuously and transparently and without any
> steps.

If my clock is set to Mon Nov 23 08:22:48 GMT 2015, chrony does not
seem to be fast to bring it to current actual time, therefore a step
is needed, but the requirement is that it cannot step during computer
activity but at shutdown process.


>>  My requirements need to sync time only at shutdown, but time cannot
>> change during machine activity, if I do the burst, sleep, makestep at
>> shutdown it works, but I would prefer to not have to wait.

> I really do not know what this means. Obviously you want your clock on your
> computer to keep running while you are using it. You do not want the system
> time stuck on midnight all of the time. That would certainly break
> everything. But if you run chrony while the system is running, your clock
> will not only
> run continuously, but will also not step. Its rate will simply be increased
> or
> decreased until your clock keeps step with the external clock. So you will
> need to be more specific with what you really want.

Of course I want clock to behave as a clock and I expect it to tick,
but I have a hard requirement that it cannot step during computer
activity. In the above case where date is set to Mon Nov 23 08:22:48
GMT 2015, I am trying to force a step at shutdown, so next time
computer gets running, it might have a close enough time to current
actual time.


>>  What I am planning to do is to have a systemd unit file that
>> triggers the burst at machine startup, then does the makestep at
>> shutdown, that way I believe clock should only step at shutdown
>
>
> What? why would you do that? It is very unclear what problem you are trying
> to
> solve, but this does not seem to be the solution to any problem I can think
> of. Chrony is NOT like ntpdate. It does not steop the clock each time it
> runs.

Miroslav has been of great help to understand what's going on. I am
now testing the following:
* set old time
* reboot machine, expecting NM hooks get source servers online
* wait 17 minutes for chronyd to take measurements
* run makestep

I hope that brings time to current.

Regards,
-- 
 Héctor Orón  -.. . -... .. .- -.   -.. . ...- . .-.. --- .--. . ..-.

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