def _vm_get_root_disk_size_from_marketplace(disk_source, config_holder): image = Image(config_holder) image_id = _disk_source_get_image_id(disk_source) size_bytes = image._getImageElementValue('bytes', image_id) # NB! PDisk "rounds" the required volume size before creation by adding 1GB. return 1 + int(size_bytes) / 1024 ** 3