Custom Controller for Agones Game Servers

This Custom Controller example shows how to create, deploy and run a Custom Kubernetes Controller for Agones that logs changes to GameServers and modifies their labels.

Prerequisite

To get started, ensure the following prerequisites are met:

  • You have a running Kubernetes cluster.

  • Agones is installed on your cluster. Refer Agones guide.

  • (Optional) Review Custom Controller code to see the details of this example.

Create a Custom Controller

Let’s create a custom controller on your cluster using the following command:

kubectl apply -f https://raw.githubusercontent.com/googleforgames/agones/release-1.40.0/examples/custom-controller/deployment.yaml

When you run this command, it quickly sets up your controller by doing four things:

  • Sets up the appropriate RBAC permissions for the custom controller
  • Launching two controllers for reliability, with leader election setup between them.

Verify the Controller

To ensure the custom controller is operational, execute the following command. You should see two instances of the controller actively running with the prefix custom-controller:

kubectl get pods -n agones-system

You should see a successful output similar to this:

NAME                                 READY   STATUS    RESTARTS   AGE
custom-controller-74c798cfd8-ld6wk   1/1     Running   0          84s
custom-controller-74c798cfd8-whpp2   1/1     Running   0          84s

Create a Fleet

Let’s create a Fleet using the following command:

kubectl apply -f https://raw.githubusercontent.com/googleforgames/agones/release-1.40.0/examples/simple-game-server/fleet.yaml

You should see a successful output similar to this :

fleet.agones.dev/simple-game-server created

This has created a Fleet record inside Kubernetes, which in turn creates two ready GameServers that are available to be allocated for a game session.

kubectl get fleet

It should look something like this:

NAME                 SCHEDULING   DESIRED   CURRENT   ALLOCATED   READY     AGE
simple-game-server   Packed       2         3         0           2         9m

You can also see the GameServers that have been created by the Fleet by running kubectl get gameservers, the GameServer will be prefixed by simple-game-server.

NAME                             STATE     ADDRESS            PORT   NODE      AGE
simple-game-server-llg4x-rx6rc   Ready     192.168.122.205    7752   minikube   9m
simple-game-server-llg4x-v6g2r   Ready     192.168.122.205    7623   minikube   9m

For the full details of the YAML file head to the Fleet Specification Guide

Monitor the log events for the custom controller pod

To monitor the logs of the custom controller during the creation, modification, and deletion of game servers, use the following command:

kubectl logs -f deployments/custom-controller -n agones-system

Note: If this controller fails for any reason, we’ve also implemented leader election such that the backup controller will automatically assume the leadership role, ensuring uninterrupted logging of event details.

Cleaning Up

When you’re done with the Agones fleet and the custom controller, it’s a good practice to clean up the resources to prevent unnecessary resource consumption. Follow these steps to remove them:

Remove the Fleet

To delete the Agones fleet you deployed, execute the following command. This will remove the fleet along with all the game server instances it manages:

kubectl delete -f https://raw.githubusercontent.com/googleforgames/agones/release-1.40.0/examples/simple-game-server/fleet.yaml

Remove the Custom Controller

To remove the custom controller from your cluster, execute the following command. This will delete the deployment that you created earlier.

kubectl delete -f https://raw.githubusercontent.com/googleforgames/agones/release-1.40.0/examples/custom-controller/deployment.yaml

Last modified May 24, 2024: docs: improve counter and list example comments (#3818) (08039d7)