[Openstack-operators] Nova API rate limiting

Robert Collins robertc at robertcollins.net
Fri Jun 28 01:16:25 UTC 2013


On 28 June 2013 12:02, Joshua Harlow <harlowja at yahoo-inc.com> wrote:
> Also note that the default rate limiting implementation is in memory.
>
> So if u are running nova in forking 'mode' then each fork will have its own
> copy of that rate limit information and thus the real rate limit will be (N
> x rate_limit) with N forks.
>
> At least I believe this is correct. So be careful with that, it would be
> nice to have a better impl (maybe using turnstile?) as the default someday.

>From a production perspective I'd much rather deal with overload
holistically: e.g. by looking at mean and 95% time to service and
delay in queue - rather than letting requests get deep into the wsgi
stack (e.g. authenticated etc).

Something like haproxy is designed to do this efficiently and at
scale, for many thousands of requests/sec per proxy.

-Rob

-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Cloud Services



More information about the OpenStack-operators mailing list