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
