kryoniteorg/kryo-server-discovery

A Velocity proxy plugin for Minecraft server discovery in k8s. All discovered servers are automatically added to the Velocity proxy.

kryo-server-discovery

This plugin connects minecraft servers to a velocity proxy within Kubernetes.

The service account in the namespace which the proxy is running in needs the privilege to read endpoints from the namespaces where the minecraft servers are running in

Setup

Minecraft servers are discovered by labels. The namespaces where the Minecraft servers are running in have to be labeled with server-discovery: "true". The pods which the minecraft server is running in has to be labeled with server-discovery: "true" as well.

Examples

Namespace:

apiVersion: v1
kind: Namespace
metadata:
  name: minecraft
  labels:
    server-discovery: "true"

Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: minecraft
  namespace: minecraft
  labels:
    app: minecraft
spec:
  replicas: 1
  selector:
    matchLabels:
      app: minecraft
  template:
    metadata:
      labels:
        app: minecraft
        server-discovery: "true"
    spec:
      containers:
      - name: minecraft
        image: minecraft

Role and role bindings

Role in the namespace where the minecraft servers are running in:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: minecraft
  name: minecraft-role
rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["list"]

Corresponding role binding to the namespace where the proxy is running in:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: minecraft-role-binding
  namespace: minecraft
subjects:
  - kind: ServiceAccount
    name: default
    namespace: proxy
roleRef:
  kind: Role
  name: minecraft-role
  apiGroup: rbac.authorization.k8s.io

A cluster role has to be defined to list namespaces:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: namespace-reader
rules:
- apiGroups: [""]
  resources: ["namespaces"]
  verbs: ["list"]

The role binding for the cluster role could look like the following:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: read-namespace-global
subjects:
  - kind: ServiceAccount
    name: default
    namespace: proxy
roleRef:
  kind: ClusterRole
  name: namespace-reader
  apiGroup: rbac.authorization.k8s.io