Description of problem:
FFU fails during converge due to the horizon container not coming back online

Version-Release number of selected component (if applicable):
From OSP13 2021-01-20.1
To: RHOS-16.1-RHEL-8-20210120.n.1

How reproducible:
Not yet known

Steps to Reproduce:
1. Deploy osp13
2. Run FFU
3. Fails during FFU converge

Actual results:
Horizon container fails to start (only up a few seconds at a time between restarts). horizon log on the container only has two entries:
[root@controller-0 ~]# cat /var/log/containers/horizon/horizon.log
2021-01-26 00:23:21,049 85 INFO openstack_auth.plugin.base Attempted scope to domain Default failed, will attemptto scope to another domain.
2021-01-26 00:23:21,304 85 INFO openstack_auth.forms Login successful for user "tempest-TestDashboardBasicOps-520537145" using domain "Default", remote address <REDACTED IP>

Expected results:
FFU should pass

Additional info:
Already on rhel8.2, use podman