Rather than using an SQL
CREATE USER query, Virtualmin uses
insert into user (with the mysql database active) when creating a user for a Virtualmin-managed database for a virtual server. This bypasses the
default_authentication_plugin setting in the MySQL 8 config, and therefore using the
caching_sha2_password password hashing method instead of the server admin's
mysql_native_password override. (Running
CREATE USER manually uses the admin-specified password hashing method.)
The error that older clients (e.g. PHP prior to v7.4) get when attempting to connect to a Virtualmin-created database is "The server requested authentication method unknown to the client".
I'm running Virtualmin version 6.08.gpl on Ubuntu Linux 18.04.3 .