Openstack multiple cinder backend

parameter_defaults:
  ControllerExtraConfig:
    cinder::config::cinder_config:

        rbd-ssd/volume_backend_name:
            value: rbd-ssd
        rbd-ssd/volume_driver:
            value: cinder.volume.drivers.rbd.RBDDriver
        rbd-ssd/rbd_ceph_conf:
            value: /etc/ceph/ceph2.conf
        rbd-ssd/rbd_user:
            value: openstack
        rbd-ssd/rbd_pool:
            value: volumes
        rbd-ssd/rbd_flatten_volume_from_snapshot:
            value: False
        rbd-ssd/rbd_secret_uuid:
            value: b90a96f8-7bee-41b2-ac0e-bea083261177
        rbd-ssd/report_discard_supported:
            value: True

    cinder_user_enabled_backends: ['rbd-ssd']