Table of Contents

• Abstract
• Installation
• How It Works
• Known Issues

Abstract

The purpose of this project is to provide a simple way to run a minecraft with the following benefits

• Minimal maintenance
• Easy to change the server version
• Automatic security updates
• More security due to deelevated permissions
• The server automatically goes to sleep when nobody is online and wakes back up when someone joins to avoid idle memory and cpu usage

Installation

1. Make sure you have docker installed

2. Make sure you have docker compose

3. Copy the following docker-compose.yml file (you can also find it in the source code):

version: "3.9"
services:
  minecraft:
    container_name: minecraft
    image: opisek/mc-paper-docker:latest
    volumes:
      - /srv/minecraft:/app/minecraft # change /srv/minecraft to the directory you want to store minecraft files in
      - minecraft-data:/app/data
    network_mode: host
    environment:
      - EULA=false      # change this to true if you agree to minecraft eula https://www.minecraft.net/en-us/eula
      - VERSION=latest  # minecraft version or "latest"
      - CHANNEL=default # change this to experimental for experimental paper builds
      - GRACE=180       # amount of time in seconds of nobody being online before stopping the server
      - XMS=8G          # minimum amount of ram to allocate to the server
      - XMX=8G          # maximum amount of ram to allocate to the server
      - UID=9999        # minecraft files user id
      - GID=9999        # minecraft files group id
    restart: unless-stopped
    stdin_open: true
    tty: true
    build:
      context: .
      dockerfile: Dockerfile
volumes:
  minecraft-data:

4. Adjust the mount point for minecraft files in the docker-compose.yml file.

For example, if you want your minecraft files to be on your Desktop and you're using Windows, you should adjust the corresponding line to

- "C:/Users/Username/Desktop/minecraft:/app/minecraft"

5. Adjust the environmental variables in the docker-compose.yml file.

For an explanation of the variables, consult the following table:

Variable	Meaning
EULA	Should be true if you agree to Minecraft's EULA
VERSION	The minecraft version that should be installed, e.g. 1.20.1 or latest for the most current version
CHANNEL	The channel for PaperMC builds to be used: default for normal builds and experimental for potentally unstable builds
GRACE	The amount to time to wait before putting the server to sleep when nobody is online
XMX	The minimum amount of RAM to allocate to the minecraft server
XMX	The maximum amount of RAM to allocate to the minecraft server
UID	The user id to use for the server files
GID	The group id to use for the server files

6. Open the directory with the docker-compose.yml file and run

docker-compose up . -d

7. Run the following command to view the server console

docker attach minecraft 

8. Once the server has booted up, make sure to add yourself to the list of operators

op Username 

9. You can now close the terminal and join your minecraft server.

How It Works

The docker container runs a Node.js script that

• Downloads the latest build of the requested minecraft version
• Runs the Minecraft server
• Periodically checks how many players are online
• Once there have been no players online for the duration of the grace period, the Minecraft server shuts down
• Now, a mock server is started, that emulates your server in Minecraft's server selection menu. It uses the same motd, player count, and server icon, as your real server.
• The moment somebody tries to join the mock server, it is closed, and we go back to the first step

Known Issues

• The mock server doesn't respect IP bans:

  If someone is ip-banned, they are still able to join the mock server, and by that, start the real server. They still cannot join the real server, only trigger the startup.

• The mock server doesn't respect the "enableStatus" property of server.properties.

  The status should not be displayed in the server selection menu if this property is set to true, however the mock server will always display the status.

• In case the latest version only has experimantal builds, but the default channel has been selected, then the installer will fail to download any binaries.

• There might be a very small chance that the stdout buffers don't include the full line, which would cause the employed regexes to fail.