Volume marked as available after a failure to build

[Lee Yarwood]

Description
===========
When skipping the scheduler by specifying a host in the provided availability_zone parameter of a request ('$az:$host') any failure to build an instance with volumes attached on the target host will result in the removal of all volume attachments within Cinder. This in turn marks this volume as available, allowing future requests to potentially use the volume.

This is due to the following exception handling code being used when no retry info is provided when skipping the scheduler:

https://github.com/openstack/nova/blob/261de76104ca67bed3ea6cdbcaaab0e44030f1e2/nova/compute/manager.py#L2225-L2241

This is contrast to what happens after a failure to schedule an instance with volumes attached where the volume attachments remain and the volume is left in a reserved state.

Steps to reproduce
==================
* Attempt to spawn an instance on a specific host using the availability_zone parameter.
* Ensure this request fails during _build_and_run_instance raising exception.RescheduledException

Expected result
===============
Any associated volumes still have attachments to the instance and are left in a reserved state.

Actual result
=============
All volume attachments are removed and any associated volumes are left in an available state.

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

   1e10461c71cb78226824988b8c903448ba7a8a76

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

   N/A

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

Logs & Configs
==============

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/757893

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/757894

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/757893
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=770c139edbd2a2c90d6cb2915948e1718dd1deca
Submitter: Zuul
Branch: master

commit 770c139edbd2a2c90d6cb2915948e1718dd1deca
Author: Lee Yarwood <email address hidden>
Date: Tue Oct 13 10:34:27 2020 +0100

    Add regression test for bug #1899649

    Related-Bug: #1899649
    Change-Id: If795b603d812917c9257ee5166a979c1fd6687f3

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 22.1.0 release.

[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/train
Review: https://review.opendev.org/c/openstack/nova/+/768180
Reason: stable/train branch of nova projects' have been tagged as End of Life. All open patches have to be abandoned in order to be able to delete the branch.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/train
Review: https://review.opendev.org/c/openstack/nova/+/768194
Reason: stable/train branch of nova projects' have been tagged as End of Life. All open patches have to be abandoned in order to be able to delete the branch.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Elod Illes <email address hidden>" on branch: stable/ussuri
Review: https://review.opendev.org/c/openstack/nova/+/764625
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/+/764626
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.