Open Stack

I've been looking at the most recent patch for this (https://review.openstack.org/#/c/117988/).

I'm wondering what behaviour do folks feel is best in the following scenario?

1) an image download starts (download1)

2) send SIGHUP to glance-api

3) start another download (download2)

4) download1 completes

5) ?

I think there's a few potential options:

5a) The request for 'download2' is never accepted (in which case
the service is 'offline' on the node until all in-flight requests are completed).

5b) The request for 'download2' is killed when 'download1' completes
and the service restarts (not much point in new SIGHUP behaviour)

5c) The request for 'download2' is accepted and completes using the
existing process, but in this case the service potentially never restarts if new
requests keep coming in

5d) A 'swift reload' type operation is done where the old processes
are left alone to complete (download1 and download2 complete) but
new parent (and child) processes are spun up to handle new requests
('download3'). The disadvantage here is some extra process accounting
and potentially stray old code running on your system

(See http://docs.openstack.org/developer/swift/admin_guide.html#swift-orphans)

-Stuart


On Mon, Jul 28, 2014 at 8:12 AM, Tailor, Rajesh <Rajesh.Tailor at nttdata.com>
wrote:

> Hi All,
>
> I have submitted the patch "Made provision for glance service to use
> Launcher" to the community gerrit.
> Pl refer: https://review.openstack.org/#/c/110012/
>
> I have also set the workflow to 'work in progress'. I will start working
> on writing unit tests for the proposed
> changes, after positive feedback for the same.
>
> Could you please give your comments on this.
>
> Could you also please suggest me whether to file a launchpad bug or a
> blueprint,  to propose these changes in the glance project ?
>

Submitting to github.com/openstack/glance-specs would be best. Thanks.


>
> Thanks,
> Rajesh Tailor
>
> -----Original Message-----
> From: Tailor, Rajesh [mailto:Rajesh.Tailor at nttdata.com]
> Sent: Wednesday, July 23, 2014 12:13 PM
> To: OpenStack Development Mailing List (not for usage questions)
> Subject: Re: [openstack-dev] [glance] Use Launcher/ProcessLauncher in
> glance
>
> Hi Jay,
> Thank you for your response.
> I will soon submit patch for the same.
>
> Thanks,
> Rajesh Tailor
>
> -----Original Message-----
> From: Jay Pipes [mailto:jaypipes at gmail.com]
> Sent: Tuesday, July 22, 2014 8:07 AM
> To: openstack-dev at lists.openstack.org
> Subject: Re: [openstack-dev] [glance] Use Launcher/ProcessLauncher in
> glance
>
> On 07/17/2014 03:07 AM, Tailor, Rajesh wrote:
> > Hi all,
> >
> > Why glance is not using Launcher/ProcessLauncher (oslo-incubator) for
> > its wsgi service like it is used in other openstack projects i.e.
> > nova, cinder, keystone etc.
>
> Glance uses the same WSGI service launch code as the other OpenStack
> project from which that code was copied: Swift.
>
> > As of now when SIGHUP signal is sent to glance-api parent process, it
> > calls the callback handler and then throws OSError.
> >
> > The OSError is thrown because os.wait system call was interrupted due
> > to SIGHUP callback handler.
> >
> > As a result of this parent process closes the server socket.
> >
> > All the child processes also gets terminated without completing
> > existing api requests because the server socket is already closed and
> > the service doesn't restart.
> >
> > Ideally when SIGHUP signal is received by the glance-api process, it
> > should process all the pending requests and then restart the
> > glance-api service.
> >
> > If (oslo-incubator) Launcher/ProcessLauncher is used in glance then it
> > will handle service restart on 'SIGHUP' signal properly.
> >
> > Can anyone please let me know what will be the positive/negative
> > impact of using Launcher/ProcessLauncher (oslo-incubator) in glance?
>
> Sounds like you've identified at least one good reason to move to
> oslo-incubator's Launcher/ProcessLauncher. Feel free to propose patches
> which introduce that change to Glance. :)
>
> > Thank You,
> >
> > Rajesh Tailor
> > ______________________________________________________________________
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> All the best,
> -jay
>
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