'nova hypervisor-servers' returns unexpected results when working with Ironic

[Tzu-Mainn Chen]

Description
===========
I have a baremetal environment using Nova to schedule on top of four Ironic baremetal nodes. I successfully deployed an instance to one of those nodes. Then I ran 'nova hypervisor-servers' against each of the nodes, and the instance showed up against every node.

Steps to reproduce
==================
After registering the nodes in Ironic and creating the server, I can see that the server is deployed on a single Ironic node:

[stack@localhost compute(keystone_admin)]$ openstack hypervisor list
+----+--------------------------------------+-----------------+-------------+-------+
| ID | Hypervisor Hostname | Hypervisor Type | Host IP | State |
+----+--------------------------------------+-----------------+-------------+-------+
| 1 | a00696d5-32ba-475e-9528-59bf11cffea6 | ironic | 192.168.1.2 | up |
| 2 | 534653c9-890d-4b25-9d6d-f4f260945384 | ironic | 192.168.1.2 | up |
| 5 | dba7d2e5-0013-48c7-8dc3-2ccc949f4715 | ironic | 192.168.1.2 | up |
| 7 | 015954fa-c900-4798-8c04-808a1504fe35 | ironic | 192.168.1.2 | up |
+----+--------------------------------------+-----------------+-------------+-------+
[stack@localhost compute(keystone_admin)]$ openstack server list
+--------------------------------------+------------+--------+----------------------------+---------+------------+
| ID | Name | Status | Networks | Image | Flavor |
+--------------------------------------+------------+--------+----------------------------+---------+------------+
| 8b09bb55-c288-4d95-8caf-60550a661350 | instance-0 | ACTIVE | provisioning=192.168.1.221 | centos7 | trait-test |
+--------------------------------------+------------+--------+----------------------------+---------+------------+
[stack@localhost compute(keystone_admin)]$ openstack baremetal node list
+--------------------------------------+---------+--------------------------------------+-------------+--------------------+-------------+
| UUID | Name | Instance UUID | Power State | Provisioning State | Maintenance |
+--------------------------------------+---------+--------------------------------------+-------------+--------------------+-------------+
| a00696d5-32ba-475e-9528-59bf11cffea6 | dell-14 | None | power off | available | False |
| 534653c9-890d-4b25-9d6d-f4f260945384 | dell-15 | None | power off | available | False |
| dba7d2e5-0013-48c7-8dc3-2ccc949f4715 | dell-12 | None | power off | available | False |
| 015954fa-c900-4798-8c04-808a1504fe35 | dell-13 | 8b09bb55-c288-4d95-8caf-60550a661350 | power on | active | False |
+--------------------------------------+---------+--------------------------------------+-------------+--------------------+-------------+

Then, if I run 'nova hypervisor-servers', the one instance shows up for multiple nodes:

[stack@localhost compute(keystone_admin)]$ nova hypervisor-servers 015954fa-c900-4798-8c04-808a1504fe35
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| ID | Name | Hypervisor ID | Hypervisor Hostname |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| 8b09bb55-c288-4d95-8caf-60550a661350 | instance-00000012 | 015954fa-c900-4798-8c04-808a1504fe35 | 015954fa-c900-4798-8c04-808a1504fe35 |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
[stack@localhost compute(keystone_admin)]$ nova hypervisor-servers a00696d5-32ba-475e-9528-59bf11cffea6
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| ID | Name | Hypervisor ID | Hypervisor Hostname |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| 8b09bb55-c288-4d95-8caf-60550a661350 | instance-00000012 | a00696d5-32ba-475e-9528-59bf11cffea6 | a00696d5-32ba-475e-9528-59bf11cffea6 |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
[stack@localhost compute(keystone_admin)]$ nova hypervisor-servers 534653c9-890d-4b25-9d6d-f4f260945384
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| ID | Name | Hypervisor ID | Hypervisor Hostname |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+
| 8b09bb55-c288-4d95-8caf-60550a661350 | instance-00000012 | 534653c9-890d-4b25-9d6d-f4f260945384 | 534653c9-890d-4b25-9d6d-f4f260945384 |
+--------------------------------------+-------------------+--------------------------------------+--------------------------------------+

Expected result
===============
The instance only shows up when 'nova hypervisor-servers' is run against the node where the instance is deployed.

Actual result
=============
The instance shows up when 'nova hypervisor-servers' is run against any node.

Environment
===========
nova @ ad842aa
ironic @ 4404292.

[Vladyslav Drok (vdrok)]

It seems that to fix this https://github.com/openstack/nova/blob/c6218428e9b29a2c52808ec7d27b4b21aadc0299/nova/api/openstack/compute/hypervisors.py#L393 should be changed to https://github.com/openstack/nova/blob/5a09c81af3b438ecbcf27fa653095ff55abb3ed4/nova/objects/instance.py#L1377-L1383, providing both compute_node.host and compute_node.hypervisor_hostname

[Matt Riedemann (mriedem)]

More details in the IRC discussion about this:

http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2019-02-13.log.html#t2019-02-13T17:34:32

But yeah that API is not baremetal-friendly and we could probably easily change that but it would require a new microversion which means a blueprint and spec:

https://docs.openstack.org/nova/latest/contributor/blueprints.html