Hello,

If you get the following error:

[FAIL] Starting MySQL database server: mysqld . . . . . . . . . . . . . . failed!

It might be because your memory is used up, normally a reboot of the server will clear up some memory, and MySQL should be able to run again. Use free -m or htop to see how much memory you have left.

A proper solution for this, is to upgrade the ram on your server or remove some processes that takes to much memory.