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Since storing the quota data in Keystone is a prereq for do the quotas in
Swift, I'm starting there. After digging through the Keystone code a bit
I've identified at least one issue with storing the quota data per tenant
for the SQL backend.

In the metadata table both tenant_id and user_id are primary keys. So the
question is, *within the current design* how do you store some piece of
metadata per tenant only?

Storing the same quota data per user for a tenant doesn't work because of
the many-to-many relationship between users and tenants.

Another option is to use a static user_id for rows where you want to store
metadata per tenant.
e.g. user_id='per_tenant_metadata',
tenant_id='55b6d515e00e48c38e2c92d27dc5c03e', data='{"quota": ...}' (I'll
figure out what the JSON looks like later)

If you retrieved the quotas via SQL it would look something like,
select data from metadata where user_id='per_tenant_metadata' and
tenant_id='55b6d515e00e48c38e2c92d27dc5c03e';

This works but doesn't feel like the cleanest solution. Any thoughts on
this approach?

Of course, stepping outside the current design would yield more options but
I wanted to look for a solution within the current design first.

Everett

On Tue, May 1, 2012 at 2:04 PM, Everett Toews <everett.toews at cybera.ca>wrote:

> Hi All,
>
> I led the session [1] on Swift Quotas at the Summit and I'd appreciate
> some feedback on the updated spec [2] and blueprint [3]. I also have a
> couple of design level questions.
>
>  1. Should we store the Swift quota data in Keystone?
>
> One of the ideas that came out of the session was that we could store the
> Swift quota data in Keystone. I took a look at Keystone and it appears the
> best place for this would be in the metada table but it appears to me that
> it's only accessible via the User Metadata Extension API in Keystone. Is it
> feasible to store the Swift quota data in Keystone this way? Should we?
>
> On a related note, during the Pluggable Tenant Data session [4] led by
> Phil Day something similar was being discussed for moving Nova quotas to
> Keystone.
>
> 2. Where should the code for Swift quotas live?
>
> It was suggested during the session that this code could live in a
> middleware for Swift. Seems like a reasonable approach to me. I've taken a
> look at some of the code in /swift/common/middleware and it looks
> relatively straight-forward. Any thoughts or suggestions on implementing
> this as middleware?
>
> Regards,
> Everett
>
> [1] http://etherpad.openstack.org/SwiftQuotas
> [2] http://wiki.openstack.org/SwiftQuotas
> [3] https://blueprints.launchpad.net/swift/+spec/storage-quotas
> [4] http://etherpad.openstack.org/FolsomPluggableTenantData
>
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