I would not include this as a part of the controller. I  don't think that every controller should install every ceph component.

Instead, you can add a group that would add this class_group to a role using the rdb backends.

I would put the following:

    roles:
      controller:
        class_groups:
          - ceph_all

in the following files:

* global_hiera_data/cinder_backend/rbd.yaml
* global_hiera_data/glance_backend/rbd.yaml