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How about sending SIGTERM to child processes and then starting them? I know
this is the hard way of achieving the objective and SIGHUP approach will
handle it more gracefully. As you mentioned it is a major change,
tentatively can we use SIGTERM to achieve the objective?


On Mon, Dec 16, 2013 at 9:50 AM, Joshua Harlow <harlowja at yahoo-inc.com>wrote:

>  In your proposal does it means that the child process will be restarted
> (that means kill -9 or sigint??). If so, without taskflow to help (or other
> solution) that means operations in progress will be corrupted/lost. That
> seems bad...
>
>  A SIGHUP approach could be handled more gracefully (but it does require
> some changes in the underlying codebase to do this "refresh").
>
>
> Sent from my really tiny device...
>
> On Dec 15, 2013, at 3:11 AM, "iKhan" <ik.ibadkhan at gmail.com> wrote:
>
>   I don't know if this is being planned in Icehouse, if not probably
> proposing an approach will help. We have seen cinder-volume service
> initialization part. Similarly if we can get our hands on child process
> that are running under cinder-volume service, if we terminate those process
> and restart them along with newly added backends. It might help us achieve
> the target.
>
>
> On Sun, Dec 15, 2013 at 12:49 PM, Joshua Harlow <harlowja at yahoo-inc.com>wrote:
>
>>  I don't currently know of a one size fits all solution here. There was
>> talk at the summit of having the cinder app respond to a SIGHUP signal and
>> attempting to reload config on this signal. Dynamic reloading is tricky
>> business (basically u need to unravel anything holding references to the
>> old config values/affected by the old config values).
>>
>>  I would start with a simple trial of this if u want to so it, part if
>> the issue will likely be oslo.config (can that library understand dynamic
>> reloading?) and then cinder drivers themselves (perhaps u need to create a
>> registry of drivers that can dynamically reload on config reloads?). Start
>> out with something simple, isolate the reloading as much as u can to a
>> single area (something like the mentioned registry of objects that can be
>> reloaded when a SIGHUP arrives) and see how it goes.
>>
>>  It does seem like a nice feature if u can get it right :-)
>>
>> Sent from my really tiny device...
>>
>> On Dec 13, 2013, at 8:57 PM, "iKhan" <ik.ibadkhan at gmail.com> wrote:
>>
>>   Hi All,
>>
>>  At present cinder driver can be only configured with adding entries in
>> conf file. Once these driver related entries are modified or added in conf
>> file, we need to restart cinder-volume service to validate the conf entries
>> and create a child process that runs in background.
>>
>>  I am thinking of a way to re-initialize or dynamically configure cinder
>> driver. So that I can accept the configuration from user on fly and perform
>> operations. I think solution lies somewhere around "oslo.config.cfg", but I
>> am still unclear about how re-initializing can be achieved.
>>
>>  Let know if anyone here is aware of any approach to re-initialize or
>> dynamically configure a driver.
>>
>>  --
>>  Thanks,
>> IK
>>
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>>
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>>
>
>
>  --
>  Thanks,
> Ibad Khan
> 9686594607
>
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>


-- 
Thanks,
Ibad Khan
9686594607
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