Oops, sent this to openstack@ not openstack-dev@. On 02/10/2015 04:52 PM, Ryan Brown wrote: > Heat team, > > After looking at Zane's prototype[1] and the ML threads on SyncPoint, I > thought it'd be helpful to make a model of *just* the logic around > resource locking. Hopefully, it'll help during implementation to be able > to see just the logic without the stubbed-out data store etc from the > prototype. > > The model[2] is the absolute minimum I could implement and still capture > what syncpoints are supposed to do. A stack is still a collection of > resources, but resources themselves are reduced to just their IDs. Locks > are still at the resource level and dependency trees are followed as in > Zane's prototype. > > Modeling it has confirmed the things we've already worked out about > SyncPoints and sharing workload across workers. Resource-level locking > is the best granularity for workers, and there isn't a case the model > checker was able to generate that breaks the resource dependency order > or ends with multiple holders of a given SyncPoint. > > It also confirms that the architecture we have is going to have serious > database overhead for managing these locks. We've been over that, and > there isn't much of a way around it without adding some other shared > synchronization system. > > If you'll be implementing convergence, please take a read over the PDF > version[3] and feedback/questions are (of course) welcome. > > Cheers, > Ryan > > [1]: https://github.com/zaneb/heat-convergence-prototype/tree/resumable > [2]: https://github.com/ryansb/heat-tla-model > [3]: https://github.com/ryansb/heat-tla-model/blob/master/Heat.pdf >
-- Ryan Brown / Software Engineer, Openstack / Red Hat, Inc. __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev