Open Stack

On 03/01/2012 02:48 PM, Vishvananda Ishaya wrote:
> On Mar 1, 2012, at 9:39 AM, Adam Young wrote:
>
>> What would the drawbacks be? Probably the first thing people would look to from Eventlet is performance. I don't have the hard numbers to compare Eventlet to Apache HTTPD, but I do know that Apache is used in enough high volume sites that I would not be overly concerned. The traffic in an Openstack deployment to a Keystone server is going to be about two orders of magnitude less than any other traffic, and is highly unlikely to be the bottleneck.
> How did you arrive at this number? Every user has to hit keystone before making a request to any other service (unless they already have a token) and each service needs to authenticate that token. Any request that hits multiple services will hit keystone multiple times.  Without caching, keystone is by far the busiest service in an openstack install. Caching should fix some of this, but I don't know that I would expect it to be two orders of magnitude less.
>
> Vish
Simply that I would expect the various servers to cache the results of 
validating a token, and thus each user-token should very quickly be 
populated on each service in the system.  If the amount of traffic 
doesn't call for caching the token,  then I expect it would be low 
enough that the issue is moot.