SLS is a declarative orchestration system for ephemeral game servers, designed especially for server networks. Everything in SLS is reproducible, isolated, and fully defined through Blueprints.

SLS runs every game server inside its own Docker container, keeping environments clean, consistent and secure.

SLS is free and open-source software licensed under AGPL-3.0.

Components

Protocube

Protocube is the core controller for SLS, responsible for managing all server instances across the system. It provides a REST API for creating, managing, and monitoring servers.

Docs:

• API Docs (Coming Soon)
• Plugin Docs (Coming Soon)
• Setup (Coming Soon)

Daemon

The server control plane for SLS. Each Daemon is responsible for provisioning, controlling and monitoring servers inside isolated Docker containers, exactly as defined by their Blueprints.

S4J

A Java wrapper for the Protocube API, providing a clean interface for plugins and external tools.

Extras

vSLS

A Velocity proxy plugin that lets you manage SLS servers directly through in-game commands.

SlimePacks

A resource pack management system that exposes API endpoints for resource pack downloads and automatically converts resource packs to the requested version using ResourcePackConverter.

Blueprints

Blueprints are declarative specifications describing exactly how a game server should run: its software, world, version, limits, configuration patches, and bundled content.

Below is a full example Blueprint.

# Blueprint metadata
blueprint:
  id: 'block_hunt'               # Unique slug ID
  name: 'Block Hunt'             # Human-readable name
  type: 'minigame'               # Arbitrary grouping tag

# World configuration
world:
  name: "Block Hunt"
  authors: "Protoxon"
  path: "minigames/block_hunt"

# Server configuration
server:
  software: "Paper"
  version: "1.18.2"
  image: "sls:java_21"

  # Resource limits
  limits:
    memory_limit: 4096
    swap: 1024
    io_weight: 500
    cpu_limit: 200
    disk_space: 10000
    threads: ""
    oom_disabled: false

  # Configuration patches
  configs:
    server.properties:
      parser: properties
      find:
        motd: "Block Hunt Server"

  # Additional files/folders bundled with the server.
  content:
    - name: "WorldEdit"
      source: "plugins/bukkit/worldedit"
    - name: "Terralith"
      source: "datapacks/terralith"
    - name: "Distant Horizons"
      source: "mods/fabric/distant_horizons"

# Whether to persist servers created from this blueprint.
# If false, the server is deleted on shutdown.
save: false

# Arbitrary metadata for external systems
annotations:
  resource_pack: "block_hunt"
  allowed_clients: "1.12..1.15, !1.13, 1.20"
  maintainer: "Protoxon"
  tags: ["hide n seek", "pvp"]

Development Status

Warning

This version of SLS is in active development and is not yet ready for use.