openstack team mailing list archive

[Eoghan Glynn <eglynn@xxxxxxxxxx>]

> > Eoghan Glynn wrote:
> >
> > - how is the mapping between project and quota-class established?
> >   I was expecting a project_quota_class_association table or
> >   some-such in the nova DB. Is this association maintained by
> >   keystone instead?
> > 
> > - is the quota_class attribute currently being set on the request
> >   context anywhere in the dispatch path? Is the idea that the auth
> >   middleware takes care of this?
> 
> Kevin Mitchell wrote:
>
> The basic answer is that there isn't anything in nova right now that
> does this, partly because it's a slightly difficult question to answer
> correctly for everyone.  In my testing environment, for instance, I use
> a Turnstile preprocessor to set the quota_class attribute on the request
> context to be the same as the selected rate limit class.
> 
> I envisioned that, ultimately, the quota_class would be set by the
> authentication processing middleware(s), but I'm not against adding
> an association to nova to manage that.

One more follow-up question on this.

So IIUC the mechanism as it currently stands implies a 1:M
mapping between quota classes and projects/tenants. Only a single
quota class may be selected for each request context, so *all* the
individual hard limits for the different resource types encompassed
by that class are inherited as default quotas for the request.

But might there be a usecase for mutiple quota classes applying to
an individual project (for different resource types)? 

e.g. compute-hungry/storage-light customers might select the
premium package for instances/cores/RAM combined with the basic
package for volumes/gigabytes (or vice versa for storage-heavy
but narrowly-scaled apps).

If we were to go down that road, we'd require an N:M association
between quota class names & projects, right? Or equivalently, a
1:M mapping between quota class IDs and projects.

Also the single quota class name in the request context would 
have to be replaced with a list of either quota class IDs or
(quota class name, resource type) pairs.

Cheers,
Eoghan