An routine scheduled update left the of the MySQL service broken today for nearly four hours. All is back to normal again.
We use MariaDB, a MySQL feature-equivalent platform for our SQL service. The updated version of MariaDB installed overnight has a bug that prevents it from starting up. The developers of cPanel has confirmed the problem and are working with the MariaDB team to have the problem fixed. In the meantime, we have rolled back to the previous version and all is back to normal. We have also cancelled further unattended system updates until we have assurances that the problem is resolved.
The MySQL service was unavailable between approximately 01:15 and 05:00 UTC. We regret the inconvenience caused.