[openstack-dev] Disable async network allocation

Aaron Rosen arosen at nicira.com
Thu Oct 24 00:56:28 UTC 2013


On Wed, Oct 23, 2013 at 4:37 PM, Nachi Ueno <nachi at ntti3.com> wrote:

> Hi Phil
>
> 2013/10/21 Day, Phil <philip.day at hp.com>:
> > Hi Folks,
> >
> >
> >
> > I’m trying to track down a couple of obsecure issues in network port
> > creation where it would be really useful if I could disable the async
> > network allocation so that everything happens in the context of a single
> > eventlet rather than two (and also rule out if there is some obscure
> > eventlet threading issue in here).   I thought it was configurable – but
> I
> > don’t see anything obvious in the code to go back to the old (slower)
> > approach of doing network allocation in-lien in the main create thread ?
> >
>
I agree, I don't see anywhere to make it configurable either

>
> May I ask the meaning of  " async network allocation" ?
>
> I believe he's referring to:
 https://github.com/openstack/nova/blob/master/nova/network/model.py#L335
https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L1211



> >
> > One of the issues I’m trying to track is Neutron occasionally creating
> more
> > than one port – I suspect a retry mechanism in the httplib2 is sending
> the
> > port create request multiple times if  Neutron is slow to reply,
> resulting
> > in Neutron processing it multiple times.  Looks like only the Neutron
> client
> > has chosen to use httplib2 rather that httplib – anyone got any insight
> here
> > ?
>
> This is a quite interest findings. so If we use httplib, this won't happen?
>
> >
> >
> > Sometimes of course the Neutron timeout results in the create request
> being
> > re-scheduled onto another node (which can it turn generate its own set of
> > port create requests).    Its the thread behavior around how the timeout
> > exception is handled that I’m slightly nervous of (some of the retries
> seem
> > to occur after the original network thread should have terminated).
> >
>
> I agree. The kind of unintentional retry causes issues.
>
> >
> > Thanks
> >
> > Phil
> >
>
> Best
> Nachi
>
> >
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> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> >
>
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