RethinkDB is used for the account, engine, service key and metadata information. It is not used to store anything about the Docker containers or images. The
/data directory is exposed as a volume.
By default, the controller will periodically report anonymous usage information. This includes things like number of engines etc. It is anonymous (not even an IP or image name is recorded). To opt-out, use the
-disable-usage-info argument when launching the controller.