Godot server in Kubernetes

The repository contains examples for deploying a Godot server on Kubernetes. It contains a Dockerfile to export your Godot project into a .pck file and bundle it into a runnable Docker image together with slim godot server binary. See Exporting for dedicated servers for more information on running Godot dedicated servers for multiplayer.

Makefile contains some examples to help you start. It assumes that you have a three server architecture (based on Godot Multiplayer Tutorial series):

• Gateway,
• Authenticate,
• Server (Game Server).

It uses kind to deploy K8s locally. But you could try with Minikube too.

Building Docker image

To build a Docker image, You need to create an export preset targetting Linux/X11. You can do it from the Godot (Project/Export.../Add preset).

docker build -f ./Dockerfile -t <image tag> --build-arg GODOT_PROJECT_NAME=<Godot project name> <path to Godot project>

For example:

docker build -f ./Dockerfile -t game-server:latest --build-arg GODOT_PROJECT_NAME=Server ./Server

Running a kind cluster

Follow instructions at https://kind.sigs.k8s.io to get kind.

Our cluster will need to expose two node ports so that our Client can connect to Gateway and GameServer services. To make it work with kind, we need to specify these node ports in a cluster configuration yaml. See kind-cluster-config.yaml

Note: Godot requires to access ports with both UDP and TCP protocols.

kind create cluster --config=kind-cluster-config.yaml

Loading our Docker images to the kind cluster

In order to use our local Docker images in kind, they need to be loaded in (see: https://kind.sigs.k8s.io/docs/user/quick-start/#loading-an-image-into-your-cluster).

kind load docker-image <image tag>

Deploying to Kubernetes

The deploy.yaml contains definitions of all resources to run the 3 servers. It exposes Gateway on NodePort 30001 and GameServer on NodePort 30000. You will need to provide these ports in Client (instead of 1909 and 1910 if you followed GDC tutorial).

Authenticate is available behind a Service named auth-server. To access it from Godot, you need provide "auth-server" as the IP of the Authenticate server. It exposes ports:

• 1911 for connection with Gateway,
• 1912 for connection with GameServer.

You will need to provide these addresses in Gateway and GameServer respectively (instead of "127.0.0.1" if you followed GDC tutorial).

Example of configurations:

# Client/GameServer.gd (script for connection with the game server)
var ip = "127.0.0.1"
#var port := 1909 # when running servers 'locally'
var port := 30000 # when running servers in Kubernetes behind NodePort

# Client/Gateway.gd (script for connection with the gateway server)
var ip = "127.0.0.1"
#var port := 1910 # when running servers 'locally'
var port := 30001 # when running servers in Kubernetes behind NodePort

# Server/HubConnection.gd (script for connection with the authorization server)
#var ip := "127.0.0.1" # when running servers 'locally'
var ip := "auth-server" # when running servers in Kubernetes
var port := 1912

# Gateway/Authenticate.gd (script for connection with the authorization server)
#var ip := "127.0.0.1" # when running servers 'locally'
var ip := "auth-server" # when running servers in Kubernetes
var port := 1911

One-click deploy with Make

Prerequisites

Code structure

The Makefile assumes you have a following directory structure:

.
├── Authenticate
├── Dockerfile (from this repo)
├── Gateway
├── kind-cluster-config.yaml (from this repo)
├── Makefile (from this repo)
└── Server

Dependencies

• export preset configured for every project
• docker installed
• kind installed
• kubectl installed (https://kubernetes.io/docs/tasks/tools/install-kubectl/)

Deploying everything in one command

Run make deploy

Verify Pods and Services

First let's check if K8s Pods are healthy. Run kubectl get pods. You should get a similar output.

NAME                              READY   STATUS    RESTARTS   AGE
auth-server-7f4579f8d-q7sfj       1/1     Running   0          119s
game-server-5f678f4648-5qc7v      1/1     Running   0          119s
gateway-server-595bd84754-b4zwp   1/1     Running   0          119s

To check Services, run kubectl get svc. Example healthy output.

NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                               AGE
auth-server      ClusterIP   10.96.54.25     <none>        1911/TCP,1911/UDP,1912/TCP,1912/UDP   2m53s
game-server      NodePort    10.96.242.166   <none>        1909:30000/TCP,1909:30000/UDP         2m53s
gateway-server   NodePort    10.96.19.68     <none>        1910:30001/TCP,1910:30001/UDP         2m53s
kubernetes       ClusterIP   10.96.0.1       <none>        443/TCP                               3m54s

TODO

• Mounting a persistent volume to Authenticate server in order to store registered users between sessions.