Kuvel

# Kuvel ## Overview Kuvel, A service discovery plugin for Velocity. It will automatically discover Minecraft servers and register/unregister them within Velocity.

## Features

Monitor Minecraft pods in a Kubernetes cluster and automatically register/unregister them within Velocity Create a LoadBalancer server and distribute players trying to join to the linked servers. * Synchronize server names across multiple Velocity instances using Redis

## Installing

The Plugin can be downloaded from (https://github.com/AzisabaNetwork/Kuvel/releases/latest). Download `Kuvel.jar` and install it into Velocity plugins directory. The config file requires initial setup as seen below.

```yml # The kubernetes namespace to use for the server discovery. namespace: "" # The prefix to use for the keys of the server labels or annotations. label-key-prefix: "kuvel.azisaba.net" # Server name synchronization by Redis is required in load-balanced environments using multiple Velocity instances. redis: group-name: "develop" connection: hostname: "redis" port: 6379 # username is optional. if you have authentication enabled, you can use it here. Otherwise you can leave it blank or null. username: "default" # password is optional. if you have authentication enabled, you can use it here. Otherwise you can leave it blank or null. password: "password"

# label-selectors are used to filter Pods and ReplicaSets to be registered. label-selectors: - "kuvel.azisaba.net/enable-server-discovery=true" ```

Alternatively you can use environment variables to configure Kuvel. The environment variable will override the config.yml and are `KUVEL_NAMESPACE`, `KUVEL_LABEL_KEY_PREFIX`, `KUVEL_REDIS_GROUPNAME`, `KUVEL_REDIS_CONNECTION_HOSTNAME`, `KUVEL_REDIS_CONNECTION_PORT`, `KUVEL_REDIS_CONNECTION_USERNAME`, and `KUVEL_REDIS_CONNECTION_PASSWORD`.

In order for Kuvel to monitor the server, you must request permission from Kubernetes. For Velocity pods, please allow get/list/watch to Pods and ReplicaSets.

```yml apiVersion: v1 kind: ServiceAccount metadata: name: velocity-account namespace: default --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: velocity-clusterrolebiding roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: view subjects: - kind: ServiceAccount name: velocity-account namespace: default ``` ```yml # Apply ServiceAccount to the Velocity pod apiVersion: apps/v1 kind: ... # ... spec: serviceAccountName: velocity-account # ... ```

## Enable Service Discovery on the Minecraft Servers

To tell Kuvel that the pod is a Minecraft server, use the Kubernetes label service. The label keys and values are specified in the config file. By default, the label key is `kuvel.azisaba.net/enable-server-discovery` and the value is `true`.

The following labels are also used for some other features.

| Label Name | Value | |:---------------------------------------:|:-----------------------------------------------------:| | kuvel.azisaba.net/preferred-server-name | Name of the server you wish to register with Velocity | | kuvel.azisaba.net/initial-server | true / false | | kuvel.azisaba.net/disable-name-suffix | true / false |

If server names longer than 63 characters are desired, the `kuvel.azisaba.net/preferred-server-name` annotation can be used instead of the label. If `kuvel.azisaba.net/disable-name-suffix=true` is set on a Pod, Kuvel will register the server name exactly as `preferred-server-name` (no `-1` suffix). If multiple replicas are detected, Kuvel logs an error and skips the extra pods. This label is intended for single-replica Pods only.

```yml apiVersion: v1 kind: Pod metadata: name: test-server labels: kuvel.azisaba.net/enable-server-discovery: "true" # Required for Kuvel to detect Minecraft servers. Depends on your config. kuvel.azisaba.net/preferred-server-name: "test-server" # Required for Kuvel to name the server # kuvel.azisaba.net/initial-server: "true" # Uncomment this line if you want to make this server the initial server. # kuvel.azisaba.net/disable-name-suffix: "true" # Use the exact preferred name (no -1 suffix); single replica only. spec: containers: - name: test-server image: itzg/minecraft-server:java8 ports: - containerPort: 25565 ```

### Deployment ```yml apiVersion: apps/v1 kind: Deployment metadata: name: test-server-deployment spec: replicas: 2 selector: matchLabels: app: test-server-deployment template: metadata: labels: app: test-server-deployment kuvel.azisaba.net/enable-server-discovery: "true" # Required for Kuvel to detect Minecraft servers. Depends on your config. kuvel.azisaba.net/preferred-server-name: "test-server" # R