Thank you very much for your reply and advice.
Compass was able to find the database.
Compass did not connect and could not find anything on 27017 when docker was not running, so it seems that it has allways connected to the intended database from docker, but I am not sure.
I could not make out if I had multiple instances running, so I made a reset of everything.
I have now de- and re-installed both compass and docker and deleted all files which have been associated with the database and made everything new.
Now after this process compass connects and actually shows the database which has not been shown previously. However all the steps in running containers in docker and connecting via compass remained the same as before. Interestingly, when compass and docker were reinstalled it showed data from the old database. Is there some sort of cache to be cleared?
Compass now shows the database running inside the linux/docker host, but unfortunately I cannot figure out what has changed.