How to start selenium hub and one linked node via docker-compose instead of using docker?

As a side note, if using docker-compose version 2 format you have to specify a couple env variables, otherwise the node will not connect to the hub:

version: '2'services:    hub:        image: selenium/hub        ports:            - "4444:4444"    firefox:        image: selenium/node-firefox        environment:            HUB_PORT_4444_TCP_ADDR: hub            HUB_PORT_4444_TCP_PORT: 4444        links:            - hub

Credits:Containers are not linked with docker-compose version 2

Stumbling across this tutorial, there was this syntax provided. And even though it's similar to one of my approaches, it worked.

hub:  image: selenium/hub  ports:    - "4444:4444"firefox:  image: selenium/node-firefox  links:    - hubchrome:  image: selenium/node-chrome  links:    - hub

It's seems to be something about the naming, yet am not sure.

selenium_hub:    image: selenium/hub    ports: ["4444:4444"]selenium_firefox_node:    image: selenium/node-firefox    links:        - "selenium_hub:hub"

While k0pernikus' answer does work, I just wanted to elaborate on the reason why it was failing.

The node containers expect to connect to a hub which is resolvable as simply:

hub

rather than in their example where it will be resolvable as:

selenium_hub