n-api should reject requests to detach a volume when the compute is down

[Lee Yarwood]

Description
===========
At present requests to detach volumes from instances on down computes are accepted by n-api but will never be acted upon if the n-cpu service hosting the instance is down.

n-api should reject such requests with a simple 409 HTTP conflict.

Steps to reproduce
==================
* Attempt to detach a volume from an instance residing on a down compute.

Expected result
===============
Request rejected by n-api

Actual result
=============
Request accepted but never completed

Environment
===========
1. Exact version of OpenStack you are running. See the following
  list for all releases: http://docs.openstack.org/releases/

   Master

2. Which hypervisor did you use?
   (For example: Libvirt + KVM, Libvirt + XEN, Hyper-V, PowerKVM, ...)
   What's the version of that?

   libvirt + QEMU/KVM

2. Which storage type did you use?
   (For example: Ceph, LVM, GPFS, ...)
   What's the version of that?

   N/A

3. Which networking type did you use?
   (For example: nova-network, Neutron with OpenVSwitch, ...)

   N/A

[sean mooney (sean-k-mooney)]

updating this to fix release sicne https://review.opendev.org/c/openstack/nova/+/768352 is merged on master

backports have been propsoed to u and v so i have add those and i also added train since i assume we want this in Train downstream?

if this need to go back futher then feel free to add those too but i tred to pick a resonable set of branches.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 23.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/ussuri
Review: https://review.opendev.org/c/openstack/nova/+/773333
Reason: stable/ussuri branch of openstack/nova transitioned to End of Life and is about to be deleted. To be able to do that, all open patches need to be abandoned.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/ussuri
Review: https://review.opendev.org/c/openstack/nova/+/773334
Reason: stable/ussuri branch of openstack/nova transitioned to End of Life and is about to be deleted. To be able to do that, all open patches need to be abandoned.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/victoria
Review: https://review.opendev.org/c/openstack/nova/+/773321
Reason: stable/victoria branch of openstack/nova is about to be deleted. To be able to do that, all open patches need to be abandoned. Please cherry pick the patch to unmaintained/victoria if you want to further work on this patch.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/victoria
Review: https://review.opendev.org/c/openstack/nova/+/773320
Reason: stable/victoria branch of openstack/nova is about to be deleted. To be able to do that, all open patches need to be abandoned. Please cherry pick the patch to unmaintained/victoria if you want to further work on this patch.