Server Maintenance Without Kicking Players Out

What actually happens to the players when we need to update the server? The simple answer would be: pull the plug. We built the better answer — and it's one of my favorite features, even though ideally you barely notice it.

The announcement. The server can send a maintenance message to every running world. In the game, a banner with a countdown then appears: "Server restart in 10 minutes." The message has to be actively dismissed — but only after a few seconds, so nobody accidentally clicks it away in the heat of battle.

The graceful restart. When the countdown expires, the world shuts down in an orderly fashion: save the game state, send players off with an explanatory farewell screen (instead of a cryptic "connection lost"), stop the container. On the next join, the world wakes up again with the new version — the save is of course still there.

The tech behind it: A secured admin endpoint accepts announcements — protected by a token that only the server knows. If no token is configured, the feature is completely off; an open announcement endpoint would be an invitation for mischief. For admins there are additionally chat commands right in the game and a per-world button in the admin panel.

An unexpected side effect: since the system has existed, we do updates more calmly — and therefore more often. Good maintenance tools don't just improve maintenance, they improve the whole project.