[openstack-dev] A new nova service? nova-periodic?

Michael Still mikal at stillhq.com
Mon Jan 14 10:22:51 UTC 2013


On Mon, Jan 14, 2013 at 9:11 PM, Daniel P. Berrange <berrange at redhat.com> wrote:
> On Sat, Jan 12, 2013 at 07:28:02PM +1100, Michael Still wrote:

>> Now that the periodic tasks refactor is done, I've just sent off a
>> code review which implements a external periodic task runner. Its at
>> https://review.openstack.org/#/c/19539/
>
> This thread has quite a large number of objections to the proposed
> introduction of this new service, which AFAIK, were never resolved.
> IMHO it is premature to be considering a merge of the feature until
> there is broad agreement that it is a good idea.

So, I re-read the thread, and there's basically one objection --
eventlet isn't true parallelism and is causing us pain. Correct me if
I'm wrong.

It seems unlikely to me that we're going to get rid of eventlet in
grizzly, or even that doing that is a good idea. There are lots of
assumptions about eventlet in the code base -- for example our locking
implementation will probably need reworking if we drop eventlet. I'd
welcome a prototype patch that demonstrated swapping out eventlet if
you'd like to contribute one.

So, there are people having problems with scale right now. What are
these people supposed to do if we can't replace eventlet anytime soon,
but you're not willing to move some periodic tasks out into another
process?

Michael



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