I just cannot get https://mariadb.com/kb/en/installing-mariadb-alongside-mysql/ to work, that eventually always ends with ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/opt/mariadb-data/mariadb.sock' (2) or something like that. I can't make sense of https://dev.mysql.com/doc/refman/8.0/en/multiple-servers.html either, especially not since I'm on Ubuntu. Can someone link/give me a guide on how to run MariaDB and MySQL at the same time?