docker-compose how to define container scoped network like in docker run?

Question

Running 2 containers where mycontainer2 must use the same network stack of mycontainer1. As if the two containers were running in the same machine. Here how I try to do by using docker run with --network container:xxx

$ docker run -it --rm --name mycontainer1 -p 6666:7777 myregistry/my-container1:latest

$ docker run -it --rm --network container:mycontainer1 --name mycontainer2 myregistry/my-container2:latest

I tried to replicate this behavior using docker-compose instead. But the networks: definition of docker-compose.yaml doesn't indicate something equivalent to the --network container:xxx option of docker run. Is it possible in docker-compose to configure two containers to use the same network stack?

Answer 1

This is a network_mode: setting.

version: '3.8'
services:
  mycontainer1:
    image: myregistry/my-container1:latest
    ports: ['6666:7777']
  mycontainer2:
    image: myregistry/my-container2:latest
    network_mode: service:mycontainer1     # <---

Since Compose will generally pick its own container names, this service:name form uses the container matching the named Compose service. (If you override container_name: then you can also use container:mycontainer1 the same way you did with docker run.)