Upgrading your game server

Thundernetes does not support the concept of rolling upgrades to the GameServerBuild. The allocation API call uses the BuildID to allocate a game server on a specific GameServerBuild, so a new GameServerBuild should be created to eventually replace the old one. In general, GameServerBuild specification should be considered immutable, except of course for the standingBy and max numbers.

To upgrade your game server process, you can follow the steps below:

• create a new GameServerBuild with a different BuildID and scale it to a high enough standingBy number of servers. Wait until the standingBy game servers are created.
• modify your matchmaker/lobby service to allocate game servers using the new BuildID.
• at the same time, set the standingBy number of the old Build to zero. Existing sessions on the old Build will eventually finish, but since the standingBy number is zero, no new game servers will be created.
• as the number of Actives on the new GameServerBuild increases, you should increase the standingBy/max numbers. Kubernetes Cluster Autoscaler should be enabled so that the number of Nodes in the cluster will increase as needed.
• once the number of Actives on the old GameServerBuild is zero, you can delete it.

NOTE: At this point, Thundernetes does not do anything to prevent you from modifying any part of the GameServerBuild specification. However, this scenario is not recommended, as it can lead to unexpected behavior.