The problem seems to be introduced by: https://opendev.org/openstack/tripleo-heat-templates/commit/cbd025a3ff465a87df5ce6847711c4dc49139e5f which is the correct solution for BZ#1944108. However, those tasks require the /etc/openstack/clouds.yaml file to be present and including the overcloud's cloud details and at the time the task is executed the content of /etc/openstack/clouds.yaml in the Undercloud is: clouds: undercloud: auth: auth_url: https://192.168.24.2:13000 password: 2ddee97afbbb34a3b3a71b86e49cafc623f30c30 project_domain_name: Default project_name: admin user_domain_name: Default username: admin cacert: '' identity_api_version: '3' region_name: regionOne Being only present the undercloud's stack information. This seems to be happening during the Undercloud upgrade, moment in which the file is being created but only the Undercloud details are added. To solve the issue we are required to execute right before the task added in https://opendev.org/openstack/tripleo-heat-templates/commit/cbd025a3ff465a87df5ce6847711c4dc49139e5f the block which takes care of updating clouds.yaml: https://opendev.org/openstack/tripleo-heat-templates/src/commit/cbd025a3ff465a87df5ce6847711c4dc49139e5f/deployment/keystone/keystone-container-puppet.yaml#L739-L771
Discovered during the testing of the proposed solution that there is another hidden issue. Cinder's v3 endpoint is still present and it needs to be cleaned up. The fix for this is proposed in https://review.opendev.org/c/openstack/tripleo-heat-templates/+/791711 which will be handled by this BZ as they are closely related.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Red Hat OpenStack Platform (RHOSP) 16.2 enhancement advisory), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2021:3483