'Brings an existing backend storage object under Cinder management.
We expect a volume name in the existing_ref that matches one in Purity.'

@pure_driver_debug_trace
def manage_existing(self, volume, existing_ref):

    self._validate_manage_existing_ref(existing_ref)
    ref_vol_name = existing_ref['name']
    current_array = self._get_current_array()
    connected_hosts = current_array.list_volume_private_connections(ref_vol_name)
    if (len(connected_hosts) > 0):
        raise exception.ManageExistingInvalidReference(existing_ref=existing_ref, reason=(_('%(driver)s    manage_existing    cannot    manage    a    volume    connected    to    hosts.    Please    disconnect    this    volume    from    existing    hosts    before    importing') % {'driver': self.__class__.__name__}))
    new_vol_name = self._get_vol_name(volume)
    LOG.info('Renaming    existing    volume    %(ref_name)s    to    %(new_name)s', {'ref_name': ref_vol_name, 'new_name': new_vol_name})
    self._rename_volume_object(ref_vol_name, new_vol_name, raise_not_exist=True)
    return None
