Jens Günther writes:
Question in general: shall I put my questions regarding docker-version on Github or is it ok on this list?
Executive summary: docker issues are specialized, just post here.
Details for the curious: Issues that only affect the docker version are going to be based on (1) network connectivity issues between the containers and (2) stuff like logging configuration where files are stored on the physical host, which has to do log rotation, but mailman lives in a container, so when logrotate does its thing it has to jump through a few extra hoops to tell mailman to reopen its log streams. Those are probably best addressed to the docker-version issue tracker on GitHub.
e.g.: now realised, that all requests are doubled, all errors, all GET-requests ... this cannot be right and probably some misconfiguration :-( would love to dig deeper and just ask myself where.
I think it's in settings.py there's a log stream that both has a file handler and is set to propagate to root, which goes to the same file. Turn off the propagation. Find the stanza by searching for "LOGGING" if I remember correctly.