1. 阐明

本博客目标：解释 docker compose 两个不同level 的 networks 作用，不便初学者。
注: 本文探讨的 Compose file format >= 3.0

2. 定义两级networks

version: "3.9"services:  proxy:    build: ./proxy    networks:  ## Service-level networks key      - frontend  app:    build: ./app    networks:  ## Service-level networks key      - frontend      - backend  db:    image: postgres    networks:      - backendnetworks:  ## Top-level networks key  frontend:    driver: brige  backend:    # Use a custom driver which takes special options    driver: brige

3. Top-level networks key

3.1 作用

指定将要创立的 networks.
(The top-level networks key lets you specify networks to be created.)
能够指定的networks 信息： driver(比方 bridge, overlay)， driver_opts 等

4. Service-level networks key

4.1 作用

指定要退出的 top-level networks key.
(Networks to join, referencing entries under the top-level networks key.)

O. 参考资料

<1> Networking in Compose
<2> top-level networks
<3> service-level networks key