T385803: deployment-prep is broken following 2025-02-06 WMCS reboots highlighted a low amount of institutional knowledge about manual actions typically needed following reboots of deployment-prep instances. We should invest time and energy in attempts to improve this.

One starting point could be adding documentation discoverable from https://wikitech.wikimedia.org/wiki/Nova_Resource:Deployment-prep on known manual needs like:

• enabling read-write mode on MariaDB servers
• arming keyholder on the deploy server
• ...