def properties_root_device_name(properties):
 root_device_name = None
 for bdm in properties.get('mappings', []):
  if (bdm['virtual'] == 'root'):
   root_device_name = bdm['device']
 if ('root_device_name' in properties):
  root_device_name = properties['root_device_name']
 return root_device_name

def properties_root_device_name ( properties ) : root_device_name = None for bdm in properties . get ( 'mappings' , [ ] ) : if ( bdm [ 'virtual' ] == 'root' ) : root_device_name = bdm [ 'device' ] if ( 'root_device_name' in properties ) : root_device_name = properties [ 'root_device_name' ] return root_device_name
get root device name from image meta data .