Subnet pools and the quota on subnets

It sounds like you want to restrict the number of subnet pools a user can get subnets from. This sounds like it should be a different quota than the subnets quota.

What is the use case or motivation behind this?

The use case is limiting the number of entries in routing tables.

I essentially want to count subnets created from a given subnet pool as one against the existing quota on number of subnets. So let's say I have a quota of 1 on number of subnets for a tenant. I want to allow the tenant to create as many subnets as he/she wants from a single subnet pool (within the limit allowed by the existing subnet pool quota). This cannot be done currently.

As you have mentioned, this is different from the current quota for subnet pools which is of value but does not provide the feature I have tried to explain here.

The feature described here cannot be satisfied by having a quota on the number of subnet pools as you are probably suggesting because if for example we add quota for subnet pools, depending on the quota on number of subnets tenants will be limited to that many subnets even though the subnets are created from the same subnet pool for example. If I put a large quota on number of subnets, since tenants are not obliged to use subnet pools, a large number of subnets can be created. If I put a small quota on number of subnets then I am limiting how many subnets from a subnet pool can be carved out. Essentially having independent quotas for subnets and subnet pools won't address the issue I have presented here.

I am not sure if I explained this well or not. If not, please let me know.

I had a quick chat with Ryan before filing this rfe where I tried to explain this feature. That conversation can be found here:
http://eavesdrop.openstack.org/irclogs/%23openstack-neutron/%23openstack-neutron.2015-07-08.log.html
starting at [17:23]

[Expired for neutron because there has been no activity for 60 days.]