Description of problem:
If DCN site is deployed without a mechanism to automatically add the DNS records into a DNS server (for example when TLS-E is used with dedicated FreeIPA server) then the deployment of the DCN site would eventually fail due to inability to resolve central site API FQDN endpoints because /etc/hosts file is not populated with DNS records of central site nodes and API endpoints.
This used to be working in some previous OSP17 ds composes but now it seems that " openstack overcloud export" command does not export ExtraHostFileEntries data.

Version-Release number of selected component (if applicable):
openstack-tripleo-heat-templates-14.3.1-0.20220607161058.ced328c.el9ost.noarch
python3-tripleoclient-16.4.1-0.20220607160517.4d2a5db.el9ost.noarch

How reproducible:
always

Steps to Reproduce:
1. Deploy a DCN env without a dedicated FreeIPA server serving as a DNS server.

Actual results:
The deployment of a DCN would fail on:
Nova: Manage aggregate and availability zone and add hosts to the zone | undercloud | error={"changed": false, "extra_data": {"data": null, "details": "Compute host dcn1-compute1-0.redhat.local could not be found.", "response": "{\"itemNotFound\": {\"code\": 404, \"message\": \"Compute host dcn1-compute1-0.redhat.local could not be found.\"}}"}, "msg": "ResourceNotFound: 404: Client Error for url: https://10.0.10.155:13774/v2.1/os-aggregates/5/action, Compute host dcn1-compute1-0.redhat.local could not be found."}

Because rabbitmq endpoint can't be resolved due to missing records in /etc/hosts on the DCN site nodes.

Expected results:


Additional info:
This used to work a couple of months ago