code: def snapshot_pool(service, pool_name, snapshot_name):
      
      cmd = ['ceph', '--id', service, 'osd', 'pool', 'mksnap', pool_name, snapshot_name]
      try:
          check_call(cmd)
      except CalledProcessError:
          raise
docs: Snapshots a RADOS pool in ceph.
      :param service: six.string_types. The Ceph user name to run the command under
      :param pool_name: six.string_types
      :param snapshot_name: six.string_types
      :return: None.  Can raise CalledProcessError