Also selenium grid docker containers. Unfortunately their Python documentation isn't the best (though there's some excellent third-party created Python documentation available). To save you the head-scratching I went through, it's basically just:

- Start a 'selenium hub'

- Start up as many firefox/chrome 'node' containers and link them to the hub.

- Point webdriver at the hub port and url.

I will eventually get around to building some Alpine containers for this, one day. I find the official ones a bit 'heavy' given all it really invoves in installing openJDK and running a jar file / browser driver.