Re: [chrony-users] Request: Add an optional timeout option for 'chronyd -q ...'

[Lonnie Abelbeck <lists@xxxxxxxxxxxxxxxxxxx>]

Hi Miroslav, (comments inline)

On Dec 1, 2016, at 5:20 AM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:

>> Does adding a "-t timeout" option to be used with "chronyd -q ..." sound reasonable ?  We would probably use -t 8 (in seconds) for the upper bound.
> 
> So you would be ok with chronyd not setting the clock? Why does it
> need to block the boot sequence then?

It is 'important' to have the clock accurately set (no stepping later) at boot before the services' daemons are started, but it is not 'critical' to do so

It is critical to not delay the boot process by more than a few seconds.  A "-t timeout_secs" option would guarantee that.


> I think a -t option might make sense in some cases, but I'm wondering
> if it rather should be a more general option to always exit after
> specified number of seconds instead of changing the behaviour of the
> -q/-Q option. I guess this could be useful with extremely long polling
> intervals. On systems with very limited memory chronyd could be
> periodically started for a short time with the -r option, and unlike
> ntpdate and other simple clients it would still be able to correct the
> frequency offset.

Certainly, If a cron job was used to periodically call chronyd instead of ntpdate, a "-t timeout_secs" option would be quite useful to make sure a stuck/delayed chronyd would not prevent later chronyd's from running.

Though, even in that case, I would expect the -q option would often be used, as the chronyd return value is often useful.

I personally don't see a case when starting chronyd as a daemon with a timeout would be useful, but you would have more insight into that than I would.  Certainly a general timeout would be welcomed.

Just to be clear, I would suggest chronyd should not return 0 if the timeout was reached and exited.


Miroslav, thanks for considering adding a "-t timeout_secs" option.

Lonnie

> 
> -- 
> Miroslav Lichvar
> 
> -- 



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