Comment 1 for bug 1918734

Hi Alexander, just to give you more insight on this one.

This is due to nova-compute (manager.py) calling for this function on cold migration:
https://opendev.org/openstack/nova/src/commit/f5f7c2540150c7ee7640c834d5caec31b3f5a7ab/nova/utils.py#L109

Because you probably don't get any DNS resolution within your underlying infrastructure, nova is actually using the /etc/hosts file to resolve your host node name.

Which in turn wrongly redirect it using your internal api subnet as the /etc/hosts file being propulated in here using the api_interface value:
https://opendev.org/openstack/kolla-ansible/src/commit/e744b9d510ba183d5a80b3e467d0e764eb5c9e02/ansible/roles/baremetal/tasks/pre-install.yml#L25

I'm having the same issue, however, before starting to fix it, I'll need to do some tests and have a few discussion with the team in order to validate that nova is the only service relying on these IPs.

For instance, changing the task to use migration_interface variable instead of the current api_interface MIGHT have an impact on RabbitMQ.