AutoStopper

AutoStopper

AutoStopper is a Velocity proxy plugin that automatically stops and starts Minecraft server containers based on player activity. It helps server administrators save resources by shutting down inactive Docker-based Minecraft servers.

Download links

- Modrinth

Features

- Automatically monitors server activity - Stops inactive Docker containers after a configurable timeout - Starts servers on-demand when players try to connect - Seamlessly connects players to servers after starting them - Maintains server state tracking

Requirements

- Velocity proxy server (3.3.0 or newer) - Docker environment with itzg/minecraft-server containers - Docker socket mounted to the Velocity container - Java 21+

Installation

1. Download the latest AutoStopper JAR from the releases page 2. Place the JAR in your Velocity server's `plugins` directory 3. Start (or restart) your Velocity server 4. Edit the generated configuration file to match your setup

Configuration

After the first run, AutoStopper will generate a `config.yml` in the `plugins/AutoStopper` directory:

```yaml

Time in seconds before an inactive server is stopped

inactivity_timeout_seconds: 900

List of servers AutoStopper should manage

monitored_servers: - server_name: purpur container_name: purpur-server - server_name: fabric container_name: fabric-server ```

Configuration Options

- `inactivity_timeout_seconds`: Time in seconds a server must be inactive before being shut down (default: 900 seconds/15 minutes) - `monitored_servers`: List of server mappings - `server_name`: Name of the server in Velocity configuration - `container_name`: Corresponding Docker container name

Docker Setup

AutoStopper requires the Docker socket to be mounted in your Velocity container. Here's an example `docker-compose.yml` setup:

```yaml services: velocity: image: itzg/mc-proxy container_name: velocity-server environment: TYPE: "VELOCITY" ONLINE_MODE: "true" VELOCITY_VERSION: "latest" VELOCITY_BUILD_ID: "latest" REPLACE_ENV_VARIABLES: "true" ports: - "25565:25565" volumes: - ./velocity_server:/server - /var/run/docker.sock:/var/run/docker.sock # Required for AutoStopper networks: - mc-network restart: unless-stopped entrypoint: bash -c command: > "if [ ! -f /usr/bin/docker ]; then apt-get update && apt-get install -y docker.io && apt-get clean; fi && SOCKET_GID=$$(stat -c '%g' /var/run/docker.sock) && if ! getent group $$SOCKET_GID > /dev/null; then groupadd -g $$SOCKET_GID docker_sock; fi && GROUP_NAME=$$(getent group $$SOCKET_GID | cut -d: -f1) && usermod -aG $$GROUP_NAME bungeecord && exec /usr/bin/run-bungeecord.sh"

Example Minecraft servers that can be managed by AutoStopper

purpur: image: itzg/minecraft-server:java21 container_name: purpur-server environment: TYPE: "PURPUR" VERSION: "1.21.4" EULA: "TRUE" ONLINE_MODE: "FALSE" volumes: - ./purpur_data:/data networks: - mc-network restart: "no" # Important: Let AutoStopper manage the container lifecycle

fabric: image: itzg/minecraft-server:java21 container_name: fabric-server environment: TYPE: "FABRIC" VERSION: "1.21.4" EULA: "TRUE" ONLINE_MODE: "FALSE" volumes: - ./fabric_data:/data networks: - mc-network restart: "no" # Important: Let AutoStopper manage the container lifecycle

networks: mc-network: driver: bridge ```

Important Docker Configuration Notes

1. The Velocity container must have Docker CLI installed, which is why the entrypoint script installs it 2. The Docker socket must be mounted (`/var/run/docker.sock:/var/run/docker.sock`) 3. The script automatically handles permissions by detecting the socket group ID and adding the server user to it. 4. Set `restart: "no"` for managed servers so Docker doesn't automatically restart them 5. Keep any hub/lobby servers with `restart: unless-stopped` if you want them to always be available

Commands

- `/autostopper` or `/as` - Main command - `/autostopper help` - Displays help information - `/autostopper status` - Shows the status of all monitored servers - `/autostopper reload` - Reloads the configuration (requires `autostopper.admin` permission)

Permissions

- `autostopper.admin` - Allows use of the reload command

How It Works

1. When a player attempts to connect to a monitored server: - If the server is running, the connection proceeds normally - If the server is stopped, AutoStopper: - Starts the Docker container - Waits for the server to fully initialize - Automatically connects the player once the server is ready

2. The plugin tracks the last activity time for each server 3. A scheduled task checks for inactive servers and stops them after the configured timeout period 4. Servers that are always needed (like hubs/lobbies) can be excluded from monitoring

Building from Source

1. Clone the repository 2. Build using Maven:

```bash mvn clean package ```

3. Find the JAR file in `target/AutoStopper-1.1.2.jar`

License

This project is licensed under the MIT License. See the LICENSE file for details.

Credits

- Built for Velocity by Criseda - Uses itzg/minecraft-server - Uses itzg/mc-proxy