I missed the first post(s) in this thread, but I should probably put out
there that I'm currently working on refactoring quotas in Nova; see:
* https://blueprints.launchpad.net/nova/+spec/quota-refactor
* https://github.com/klmitch/nova/tree/quota-atomicity
* https://review.openstack.org/#/c/6774
* https://review.openstack.org/#/c/7048
To get a sense of what I'm doing. I've also been thinking about the
constraints of an external quota manager, but haven't gotten much
further than some kind of RPC or REST-based API.
(Note I haven't been strongly considering integrating this with Keystone
for a couple of reasons: 1. I tend to prefer the UNIX paradigm of doing
one thing well; 2. I want to ensure that this external quota manager is
usable for those who choose to use something other than Keystone.)
Feel free to ask me questions; I'm sure there's a lot of stuff I've
thought of that may not be obvious from the above references, and your
questions will probably help me articulate it better :)
--
Kevin L. Mitchell <kevin.mitchell at rackspace.com>