In Openstack-Helm we use this script [1] to deploy the Rook operator and Ceph cluster. As you can see it uses official Rook helm charts with some custom values. It creates the rook-ceph-tools Deployment which creates the pod rook-ceph-tools-xxxxxxxx-yyyyy that contains some CLI tools for managing Ceph clusters. So you can run `ceph auth ls` inside this pod. If you don't have this tools pod, then you can run the command manually in a pod where this tool is available. Here is the command from the ceph-adapter-rook chart that is used to get the key.