Thank you for taking the time to file a bug report. By inspecting the logs I see that you tried to install MySQL and MariaDB together. As you might have noticed, they are incompatible with each other; therefore, when you try to install one of them, the other is automatically removed. However, this removal sometimes leaves behind some application-specific data that causes an error when the new package is installed on top of the old one.
Having said that, I investigated the problem further and was able to reproduce the error. If I start a Focal lxd container and do: # apt install mariadb-server mariadb-client && apt install mysql- client-8.0 && apt install mysql-server && apt-get install --reinstall mysql-server && apt install mariadb-client-core-10.3 The system will be left in this inconsistent state w.r.t. MySQL. Further attempts to remove/purge the mysql-server package failed, and even trying to inspect the status of mysqld.service did not work: # systemctl status mysqld.service Unit mysqld.service could not be found. I am marking this bug as Triaged; we will have to further analize what the problem is. ** Changed in: mysql-8.0 (Ubuntu) Status: New => Triaged -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1902348 Title: package mysql-server-8.0 8.0.22-0ubuntu0.20.04.2 failed to install/upgrade: installed mysql-server-8.0 package pre-removal script subprocess returned error exit status 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mysql-8.0/+bug/1902348/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs