Bug 1665506

Description of problem:
-----------------------

Previously it was possible to add additional networks to a role without
using a custom role by overriding the resource registry, for example:

resource_registry:
  OS::TripleO::Compute::Ports::ExternalPort: ../network/ports/external.yaml

Another example for Management network:

resource_registry:
  OS::TripleO::Controller::Ports::ManagmentPort: ../network/ports/management.yaml
  OS::TripleO::Compute::Ports::ManagmentPort: ../network/ports/management.yaml
  OS::TripleO::Ceph::Ports::ManagmentPort: ../network/ports/management.yaml

Adding the Management network as above used to be the way to add this network prior to Composable Networks in OSP-12.


The FFU Upgrade document is not precis about the requirement to add networks to roles data.
Documentation text is:

  """ If using a custom roles_data file, edit the file to add the composable networks to each role. """

A user adding the Management network (or any other network) using resource_registry as was the documented way to do it prior to OSP-13 would be using the default roles_data (not using custom roles data).


Version-Release number of selected component (if applicable):
-------------------------------------------------------------
https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/13/html/fast_forward_upgrades/assembly-preparing_for_overcloud_upgrade#preparing_for_composable_networks

Actual results:
---------------

The user added the Managment (or any other network) without using custom roles data.
The documented procedure only instruct to add networks if (only if) using custom roles data. This won't be sufficient once the fix for https://bugzilla.redhat.com/show_bug.cgi?id=1643423 land in the next OSP-13 maintenance release.

Expected results:
-----------------

The document must be more clear.
If any non-default network was used (such as the Management network), custom roles data with that network is now required.


Additional info:
https://review.openstack.org/#/c/629963/