Comment 1 for bug 1861401

Colleagues,

FYI

changing single line in (for Rocky) nova/network/neutronv2/api.py:

--- nova/network/neutronv2/api.py.orig 2020-02-04 08:32:33.305779575 +0000
+++ nova/network/neutronv2/api.py 2020-02-04 08:32:50.445688233 +0000
@@ -728,7 +728,7 @@
                     # dns_name attribute, it is equal to the instance's
                     # hostname
                     if port.get('dns_name'):
- if port['dns_name'] != instance.hostname:
+ if port['dns_name'] != instance.display_name:
                             raise exception.PortNotUsableDNS(
                                 port_id=request.port_id,
                                 instance=instance.uuid, value=port['dns_name'],

did the job. Same piece of code is present in current master at nova/network/neutron.py

I can submit the patch, but just don't know whether this approach will/will not break something else. It seems, no; but if anybody can clarify, it will be great.

Thank you.