Game Node migration

Migrating Game Nodes to a different server tier, usually higher, can be useful when you need to accomodate a larger number of CCUs per instance.

This operation needs to be planned carefully and requires a number of steps to reduce downtime to a minimum. By following this step-by-step guide you will be able to migrate your Game Nodes while your players continue with their activities.

It is anyways highly recommend to choose a time for the migration with a low traffic, to avoid downtimes in case something goes wrong, or any of the steps are missed.

Overview

The most important aspect to keep in mind when migrating Game servers is that the Overcast Cluster expects all Game Nodes to be the same tier. In other words they all must use the same type of machine with the same hardware specs.

Migration flow

Now let's see what are the main steps to follow:

  1. Prepare a new Game server snapshot (optional).
  2. Reconfigure the Lobby, specifying the new server tier to use for Game Nodes.
  3. Reconfigure the Orchestrator.
  4. Launch new Game Nodes.
  5. Deactivate the old Game Nodes.

1. Prepare a new Game server snapshot (optional)

This is only necessary if you're planning to use a different SFS2X configuration, or deploy new Extensions. Otherwise, if you are just moving to a different server tier, you can skip this step entirely.

If you are going to create a new snapshot also make sure to reconfigure the Lobby server by referencing the new image as the one the be used when launching new Game Nodes. This is done in the Overcast HQ, by clicking the [Actions] icon on the right hand side of the active Lobby server and selecting the Edit option.

In the next screen, open the snapshot dropdown and select the new image to use.

If you need to learn more about creating snapshots for the cluster you can read the details here.

2. Reconfigure the Lobby

Let's now change the server tier that will be used to start new Game Nodes. From the Overcast HQ select your Application, then click on the [Actions] icon on the right hand side of the active Lobby Node.

Click the Edit option and in the next page select your new tier, confirming with the Submit button.

3. Reconfigure the Orchestrator

When moving to a new server tier for Game Nodes it may be necessary to also change the Orchestrator settings via the AdminTool.

In fact here we specify the CCU thresholds for triggering the Scale-up and Scale-down events which in turn control the amount of Game Nodes in the cluster. If you're moving the Game servers to a higher tier you will likely need to adjust these settings accordingly.

To do so connect to the Lobby as admin and select the Cluster Configurator module, then apply the necessary changes.

NOTE: Orchestrator settings are applied live while the cluster is running, and no restart is required.

4. Launch new Game Nodes

Now it is time to launch at least one new Game Node manually, using the new tier. While most players are still be playing on the old servers until their current game is complete, new players in the Lobby will not have any servers to play on, once the old instances are disabled (which is our last step).

By launching at least one server new players will be able to start games there and, as the traffic grows, Game Nodes based on the new tier will be started automatically. You can also decide to launch multiple Game Nodes, if necessary.

To do so login in your Overcast HQ account, select the current Application and launch a new Game server, remembering to:

  • Set the Standalone parameter to No (so that the Node joins the cluster).
  • Choose the On-demand billing plan (so that you pay only for the lifetime of the instance).

If you need to review the process to do so, make sure to check our documentation.

5. Deactivate the old Game Nodes

Deactivating the old Game Nodes does not affect the games running on it, instead it simply excludes them from the Load Balancing algorithm. This means that current games will keep running until complete, but no new games will be started on these servers. Eventually all deactivated nodes will become empty and the Orchestrator will remove them from the cluster.

To deactivate the old Game Nodes launch the Lobby's AdminTool and select the Cluster Monitor module:

Here select the nodes to deactivate and proceed by clicking the Deactivate button. Once this is done you can still find these Nodes under the Inactive nodes list of the same panel.

NOTE: this operation is irreversibile. Once a Node has been deactivated it cannot be brought back in the cluster. The server will keep running and handling players but no new games will be started on it. The node will be terminated automatically after being empty for the amount of time defined in the cluster settings.

One last thing you should check is if you have old Game Nodes under the inactive section that are recyclable. These are empty servers that are still running and could be re-activated when a Scale-up event occurs. They are recognizable by a green light in the "R" column (for Recyclable) of the table above. These should also be removed as well.

Once this is done the operation is complete: you have fully migrated your Game Nodes to a new tier without downtimes!