You don't have to "use docker" to use Concourse. It runs docker images under the hood. It only becomes relevant when you define which container image to use to

You don't have to "use docker" to use Concourse. It runs docker images under the hood. It only becomes relevant when you define which container image to use to run things. After a little while you'll realise you want something a bit different, at which point the docker-image resource that's supported by the Concourse team makes it embarrassingly easy. You just tell Concourse "yo, push to this image" and it does the rest.