Comment 3 for bug 1781286

The except block in comment 1 is not entered, because the exception doesn't get raised until after that, line 652 in stable/queens:

https://github.com/openstack/nova/blob/7ae2dc840a0bccb868122bb4b77e8958a0e842a7/nova/conductor/manager.py#L650-L652

The links in comment 2 all appear to be from master. I wouldn't be surprised if master is also affected, but I'm seeing this in stable/queens, so we probably want to look there first.

[scheduler]max_attempts is not changed from the default (3) and the create requests do not appear to be specifying a specific host/node.