Hi, I figured out how to get docker containers to join an existing network with putting “networks” into the respective sections of the docker-compose.yml

If I want to also give them fixed ip’s on this network, what would the syntax look like in the docker-compose.yml?

  • cool_pebble@aussie.zoneEnglish
    1·
    1 year ago
    networks:
  app:
    ipam:
      config:
        - subnet: 172.20.0.0/24
          gateway: 172.20.0.1
services:
  app:
    image: my-app-image
    networks:
      app:
        ipv4_address: 172.20.0.10

    In the above example I’ve declared a Docker Bridge network with the range 172.20.0.0/24 and a gateway at 172.20.0.1. I have a service named app with a static IP of 172.20.0.10.

    The same is also possible with IPv6, though there are extra steps involved to make IPv6 networking work in Docker and it’s not enabled by default so I won’t go into detail in this comment.

    Out of curiosity, what’s the use case for a static IP in the Docker Bridge network? Docker compose assigns hostnames equal to the service name. That is, if you had another container in the app network from my example above, it could just do a DNS lookup for app and it would resolve to 172.20.0.10.