Why does sedna's Model resource have no node fields

[tangming1996]

apiVersion: sedna.io/v1alpha1
kind: Model
metadata:
name: helmet-detection-inference-big-model
namespace: default
spec:
url: "/data/big-model/yolov3_darknet.pb"
format: "pb"
？nodeName：<------ Why does the model not need the nodeName field?