dockerのコンテナに固定IPを振る(compose file version 3の注意点)

version: '3.3'

services:

  wordpress:
    image: wordpress
    restart: always
    ports:
      - 8080:80
    networks:
      app_net:
        ipv4_address: 172.30.0.3
    environment:
      - WORDPRESS_DB_PASSWORD
      - TZ

  mysql:
    image: mariadb-10.3.8:05
    build: .
    restart: always
    networks:
      app_net:
        ipv4_address: 172.30.0.2
    environment:
      - MYSQL_ROOT_PASSWORD=${WORDPRESS_DB_PASSWORD}
      - TZ

networks:
  app_net:
    driver: bridge
    ipam:
     driver: default
     config:
       - subnet: 172.30.0.0/24
         gateway: 172.30.0.1

$ sudo docker-compose up -d
RROR: The Compose file './docker-compose.yml' is invalid because:
networks.app_net.ipam.config value Additional properties are not allowed ('gateway' was unexpected)

version: '3.3'

services:
--------------------------省略-------------------
networks:
  app_net:
    driver: bridge
    ipam:
     driver: default
     config:
       - subnet: 172.30.0.0/24
#         gateway: 172.30.0.1    <-----コメントアウト

$ sudo docker-compose up -d
Creating compose_wordpress_wordpress_1 ... done
Creating compose_wordpress_mysql_1     ... done