Openstack: HEAT generation can renumber ports leading to IP conflicts

[Sidiox]

The generation of a new HEAT template after updating a topology can lead to ports being reshuffled due to not accounting for the existing HEAT template.

This then leads to conflicts when for example unit_port0 was the mgmt_interface with an 192.168.122.0/24 IP and then suddenly changes to unit_port1 for the mgmt. Openstack reports that the IP is already in use.

Edit: This only seems to happen to devices that are deployed without a connection to other devices