absolute limits API doesn't take user quotas into account

[Phil Day]

The limits API always returns the per tenant limits and not any per-user limits that may exist.

https://github.com/openstack/nova/blob/master/nova/api/openstack/compute/limits.py#L94-95

The call to get_project_quotas should be replaced with a call to get_user_quotas.

A similar problem exists in used_limits, as this reports overall tenant consumption and not the corresponding per user value.

I suspect this just got missed when per-user project quotas were introduced.

However if we do switch to showing the per user values for limits and used
it is possible that a user might see a different set of confusing values:

Project Quota = 10
User Quota = 5
User Usage = 1
Other User Usage = 9

If we show just the overall project usage and quota we get (used=10, quota=10) - which shows that the project quota is fully used.

However if we show just the user quotas we get (used=1, quota=5), which
suggests that there is capacity.

Conversely if:
Project Quota = 10
User Quota = 1
User Usage = 1
Other User Usage = 2

If we show just the overall project usage and quota we get (used=3, quota=10) - which shows that the project quota is not fully used.

However if we show just the user quotas we get (used=1, quota=1), which
suggests that this user doesn't have any available quota.

So maybe the limits API now needs to return both the project and user level limits.

[Thang Pham (thang-pham)]

Is this related? https://bugs.launchpad.net/nova/+bug/1334278

[Thang Pham (thang-pham)]

I am looking into this and working on getting a patch out soon. Just to clarify - nova absolute-limits has the following options: nova absolute-limits [--tenant [<tenant>]] [--reserved]

Are you saying that "nova absolute-limits" should just return the user quotas, and "nova absolute-limits --tenant foobar" should return the project quotas? More specifically:

"nova absolute-limits" should call: QUOTAS.get_user_quotas(context, project_id, user_id)
"nova absolute-limits --tenant foobar" should call: QUOTAS.get_project_quotas(context, project_id)

Or are you saying that the list of limits returned should combine the results (which would require a nova-spec I think)? For example:
+-----------------------------+-------+----------------+
| Quota | Limit | Project Limit |
+-----------------------------+-------+----------------+
| instances | 10 | 20 |
| cores | 20 | 40 |
| ram | 51200 | 102400 |
...
+-----------------------------+-------+----------------+

[Phil Day (philip-day)]

Hi,

I did some more thinking about this - and I think that only presenting one set of limits at a time (user or project) will always be confusing to someone. So I think the only clean way to fix this is to provide both the user and project values in the same response - and that is an API change that probably would need a nova-spec.

[Thang Pham (thang-pham)]

Ok. I will craft up a nova-spec for this (have to wait until kilo opens up). It would be nice to include the tenant absolute-limits in the response and have the novaclient show two columns, e.g.

+-------------------------+-------+-------+
| Name | User-Value | Project-Value |
+-------------------------+-------+-------+
| maxServerMeta | 128 | 128 |
| maxPersonality | 1 | 5 |
...

[Markus Zoeller (markus_z) (mzoeller)]

This wishlist bug has been open a year without any activity. I'm going to move it to "Opinion / Wishlist", which is an easily-obtainable queue of older requests that have come on.

In case you want to work on that, consider writing a blueprints [1] and spec [2]. I'll recommend to read [3] if not yet done. The effort to implement the requested feature is then driven only by the blueprint (and spec).

References:
[1] https://blueprints.launchpad.net/nova/
[2] https://github.com/openstack/nova-specs
[3] https://wiki.openstack.org/wiki/Blueprints