What is the probability and severity of the issue? I.e. the overall risk

Changes in 18 were made to support clone v2 and to leverage RBD trash to fix volume deletion – this means that Cinder RBD functionality needs to be regression tested thoroughly.  (This is why this change targets GA rather than a later feature pack.)

Does this affect specific configurations, hardware, environmental factors, etc.?

Deployments that use Ceph

Are any partners relying on this functionality in order to ship an ecosystem product?

Not sure, mostly relevant for RHCS.

What proportion of our customers could hit this issue?

Anyone using Ceph with Cinder

Does this happen for only a specific use case?

Ceph being used for Cinder storage

What proportion of our CI infrastructure, automation, and test cases does this issue impact?

Jobs that test w/ Ceph

Is this a regression in supported functionality from a previous release?

No

Is there a clear workaround?

No

Is there potential doc impact?

Yes

If this is a UI issue:
Is the UI still fit for its purpose/goal?

N/A

Does the bug compromise the overall trustworthiness of the UI?

N/A

Overall context and effort – is the overall impact bigger/worse than the bug in isolation? For example, 1 workaround might seem ok, 5 is getting ugly, 20 might be unacceptable (rough numbers).

Small – this is about regression testing, now.