"Quota exceeded" message is confusing for "resize"

[Belmiro Moreira]

"Quota exceeded" message is confusing for "resize"

When trying to create an instance and there is no quota available, the user gets an error message.
example:
"Quota exceeded for cores: Requested 1, but already used 100 of 100 cores (HTTP 403)"

The user can see that the project is already using 100 vCPUs out of 100 vCPUs available (vCPU quota) in the project.

However, if he tries to resize an instance we can get a similar error message:
"Quota exceeded for cores: Requested 2, but already used 42 of 100 cores (HTTP 403)"

So, this has a completely different meaning!
It means that the user (of the instance that he's trying to resize) is using 42 vCPUs in the project out of 100 cores allowed by the quota.

This is hard to understand for a end user.
When naively reading this message looks like the project still has plenty of resources for the resize.

I believe this comes from the time when Nova allowed quotas per user.
In my opinion this distinction shouldn't be done anymore. As mentioned we don't do it when creating a new instance.

+++

This was tested with the master branch (19/11/2021)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/820898