Description of problem:
For Databases, upgrade of the OS is always a sensitive event, and in many cases the major version of the database server is changed.

The upgrade should be more described in a Migration guide and/or a KB article.

When the system looks like it includes an initialized database, the LEAPP tool should warn users ahead about possible issues during the upgrade, the need of a proper backup, and ideally at least point to that documentation,

This bug is supposed to track the work on creating such a LEAPP actor that would help database users before the upgrade itself.

Before there is some more concrete documentation, the doc for 7 to 8 migration might be used:
https://leapp.readthedocs.io/en/latest/el7toel8/actor-rhel7-to-rhel8.html

We're currently looking for something similar to the PostgreSQL actor for helping with 7 to 8 migration:
https://github.com/oamg/leapp-repository/blob/c4e6a10cb78f6cdd08b89f0ad938576d8ecbf28f/repos/system_upgrade/el7toel8/actors/postgresqlcheck/libraries/postgresqlcheck.py

But in this case for 8->9 migration and for MySQL component.