...The "dynamic" execution mode needs to be told what Docker images to use when the containers get started. Additionally, the Grid needs to know the URI of the Docker daemon. If you want to scale by distributing and running tests on several machines and manage multiple environments from a central point, making it easy to run the tests against a vast combination of browsers/OS, then you want to use Selenium Grid. It is possible to start a Selenium Grid with all its components apart. For simplicity, only an example with docker-compose will be provided. ...