See below

Chapter 7. Subscriptions

To install Red Hat OpenStack Services on OpenShift (RHOSO), you must register all systems in the RHOSO environment with Red Hat Subscription Manager, and subscribe to the required channels. For more information about the channels and repositories to deploy RHOSO, see ???

direct link:
https://access.redhat.com/documentation/en-us/red_hat_openstack_services_on_openshift/18.0-beta/html/planning_your_deployment/ref_subscriptions_planning