Could supplemental Groups be used for ceph rbd?

Hi, I setup ceph rbd with openshift origin 3.6. I read document about ceph volume and volume security. https://docs.okd.io/3.6/install_config/persistent_storage/pod_security_context.html#supplemental-groups

Re: okd 3.11: recommended procedure to create admin account?

Unfortunately, there is no way to set cluster-admin cluster role to a specific user through ansible playbooks. You will need to do so manually. Also, I'm wondering why you manually create a clusterrolebinding object instead of using "oc adm policy add-cluster-role-to-user" command. The easiest