Yes thank you, I have tried specifying the port at the CLI too... that did not help.
But restarting PostgreSQL in my custom /docker-entrypoint-initdb.d/run-after-initdb.sh has helped, even though I am not sure if it is the best way: #!/bin/sh LANGUAGES="de en fr nl pl ru" createuser --username=postgres words psql --username=postgres -c "GRANT USAGE ON SCHEMA public TO words;" psql --username=postgres -c "ALTER USER words PASSWORD 'mypassword';" for L in $LANGUAGES; do createdb --username=postgres --owner=words words_$L cd /dict/$L && psql words_$L < words_$L.sql done # Restart PostgreSQL to make it listen at localhost too pg_ctl --options "-c listen_addresses='localhost'" --wait restart