I think your question was not clearly enough referring to using Geonetwork
with docker. Also your issue is more about database and docker than it is
about Geonetwork, which handles user passwords the same way as any other
I still think GIS SE is the right place to discuss user issues for
Geonetwork (functional or technical), but the community site might indeed
be clearer on the fact that issues need to be somehow related to GIS.
Anyway, there's still a lot of support questions asked on the mailing lists
and very few answers on SE, so there's that...
BY OPEN SOURCE EXPERTS