Fabric Server - Docker Minecraft Server

Fabric is a lightweight, modern modding toolchain for Minecraft that provides a clean, minimal framework for mods. It’s designed for quick updates and performance, making it ideal for running modded servers.

Overview

Fabric offers several advantages for modded Minecraft servers:

Quick Updates: Usually available for new Minecraft versions within hours
Lightweight: Minimal overhead compared to other modding platforms
Modern Architecture: Clean API design and good performance
Growing Ecosystem: Large collection of optimization and content mods
Active Community: Regular updates and community support

Fabric mods are NOT compatible with Forge mods. If you need to run both types, consider hybrid servers.

Configuration

Basic Setup

services:
  minecraft:
    image: itzg/minecraft-server
    environment:
      EULA: "TRUE"
      TYPE: FABRIC
      VERSION: "1.20.4"
    ports:
      - "25565:25565"
    volumes:
      - ./data:/data
    restart: unless-stopped

Version Selection

Automatic Latest Versions

By default, Fabric installs the latest launcher and loader for your Minecraft version:

environment:
  TYPE: FABRIC
  VERSION: "1.20.4"  # Minecraft version

This configuration automatically:

Downloads the latest Fabric server launcher
Installs the latest Fabric loader
Uses the specified Minecraft version (or latest if omitted)

Specific Loader Version

Select a specific Fabric loader version:

environment:
  TYPE: FABRIC
  VERSION: "1.20.4"
  FABRIC_LOADER_VERSION: "0.13.1"

Specific Launcher Version

Select a specific Fabric launcher version:

environment:
  TYPE: FABRIC
  FABRIC_LAUNCHER_VERSION: "0.10.2"
  FABRIC_LOADER_VERSION: "0.13.1"

Environment Variables

Variable	Default	Description
`TYPE`	-	Set to `FABRIC`
`VERSION`	latest	Minecraft version (e.g., `1.20.4`)
`FABRIC_LOADER_VERSION`	latest	Fabric loader version
`FABRIC_LAUNCHER_VERSION`	latest	Fabric launcher version
`FABRIC_LAUNCHER`	-	Path to custom launcher JAR (relative to `/data`)
`FABRIC_LAUNCHER_URL`	-	URL to download custom launcher
`FABRIC_META_BASE_URL`	`https://meta.fabricmc.net`	Fabric meta API base URL
`FABRIC_FORCE_REINSTALL`	`false`	Force reinstall Fabric launcher

Installing Fabric API

Most Fabric mods require the Fabric API mod to be installed. The easiest way to install it is using Modrinth:

environment:
  TYPE: FABRIC
  VERSION: "1.20.4"
  MODRINTH_PROJECTS: |
    fabric-api

Fabric API is a library mod that provides essential hooks for other Fabric mods. Almost all Fabric mods depend on it.

Mod Management

Manual Mod Installation

Place Fabric mods (.jar files) in the mods directory:

Mount mods directory

volumes:
  - ./data:/data
  - ./mods:/data/mods

Add mod files

Download Fabric mods from Modrinth or CurseForge and place .jar files in ./mods/.

Restart server

docker restart minecraft-fabric

Auto-Download from Modrinth

Automatically download and install Fabric mods from Modrinth:

environment:
  TYPE: FABRIC
  VERSION: "1.20.4"
  MODRINTH_PROJECTS: |
    fabric-api
    lithium
    phosphor
    sodium

Auto-Download from CurseForge

Download mods from CurseForge:

environment:
  TYPE: FABRIC
  CF_API_KEY: "your-api-key"
  CF_SLUG: "fabric-api,lithium"

Ensure mods are compatible with both your Minecraft version and Fabric loader version. Check mod requirements before installing.

Popular Fabric Mods

Performance Optimization

environment:
  TYPE: FABRIC
  VERSION: "1.20.4"
  MODRINTH_PROJECTS: |
    fabric-api
    lithium        # Server optimization
    phosphor       # Lighting engine optimization  
    ferritecore    # Memory optimization
    krypton        # Network optimization
    c2me-fabric    # Chunk performance

Server Administration

environment:
  MODRINTH_PROJECTS: |
    fabric-api
    fabric-permissions-api
    luckperms      # Permissions management
    chunky         # Pre-generation

Quality of Life

environment:
  MODRINTH_PROJECTS: |
    fabric-api
    carpet         # Carpet mod for technical features
    ledger         # Block logging

Advanced Configuration

Custom Fabric Launcher

Use a custom Fabric launcher from a URL:

environment:
  TYPE: FABRIC
  FABRIC_LAUNCHER_URL: "http://your-server.com/fabric-server-custom.jar"

Or from a file path (relative to /data):

environment:
  TYPE: FABRIC
  FABRIC_LAUNCHER: "fabric-server-custom.jar"
volumes:
  - ./fabric-server-custom.jar:/data/fabric-server-custom.jar

Custom Meta API

Use a custom or mirrored Fabric meta API:

environment:
  TYPE: FABRIC
  FABRIC_META_BASE_URL: "https://your-mirror.com/fabric-meta"

Force Reinstall

If the Fabric launcher becomes corrupted:

environment:
  FABRIC_FORCE_REINSTALL: "true"

Remove FABRIC_FORCE_REINSTALL after successfully reinstalling.

Complete Production Example

docker-compose.yml

services:
  minecraft:
    image: itzg/minecraft-server
    container_name: minecraft-fabric
    
    environment:
      # Server Type
      EULA: "TRUE"
      TYPE: FABRIC
      VERSION: "1.20.4"
      FABRIC_LOADER_VERSION: "0.15.0"
      
      # Auto-install Fabric API and optimization mods
      MODRINTH_PROJECTS: |
        fabric-api
        lithium
        phosphor
        ferritecore
        krypton
        luckperms
      
      # Server Settings
      MOTD: "A Fabric Minecraft Server"
      DIFFICULTY: normal
      MODE: survival
      MAX_PLAYERS: 50
      VIEW_DISTANCE: 12
      SIMULATION_DISTANCE: 8
      
      # Performance
      MEMORY: 6G
      USE_AIKAR_FLAGS: "true"
      
      # World
      LEVEL: "world"
      SEED: "fabric-world"
      
      # Security
      ENABLE_WHITELIST: "false"
      ONLINE_MODE: "true"
    
    ports:
      - "25565:25565"
    
    volumes:
      - ./data:/data
      - ./mods:/data/mods
      - ./config:/data/config
    
    restart: unless-stopped
    
    stdin_open: true
    tty: true

Mod Configuration

Config Files

Mod configurations are stored in the config directory:

volumes:
  - ./data:/data
  - ./config:/data/config

Each mod typically creates its own config file:

./config/lithium.properties
./config/phosphor.properties
./config/carpet.conf

Server-Side vs Client-Side Mods

Server-Side Mods (work on server only):

Lithium (performance)
Phosphor (lighting)
Carpet (technical features)
FerriteCore (memory)

Client-Side Mods (require client installation):

Sodium (rendering)
Iris (shaders)
Mod Menu

Universal Mods (work on both):

Fabric API
Many content mods

Only install server-side or universal mods on your server. Client-side rendering mods won’t work on servers.

Performance Tuning

Recommended Mods for Performance

environment:
  MODRINTH_PROJECTS: |
    fabric-api
    lithium        # Overall performance
    phosphor       # Lighting performance
    ferritecore    # Memory usage reduction
    krypton        # Network performance
    c2me-fabric    # Chunk performance
    starlight      # Alternative lighting engine

Memory Allocation

environment:
  MEMORY: 6G  # For modded servers with 20-30 players
  USE_AIKAR_FLAGS: "true"

Players	Mods	Recommended RAM
1-10	Light	4GB
10-20	Medium	6GB
20-50	Medium	8GB
50+	Heavy	12GB+

Troubleshooting

Corrupted Launcher

Force reinstall the Fabric launcher:

environment:
  FABRIC_FORCE_REINSTALL: "true"

Mod Compatibility Issues

Check mod requirements on Modrinth/CurseForge
Verify Minecraft version compatibility
Ensure Fabric API is installed
Check server logs for specific errors

Version Mismatch

If mods fail to load:

Verify mod supports your Minecraft version
Check Fabric loader version compatibility
Update mods to compatible versions

Migration Guide

From Vanilla to Fabric

Backup your world

docker stop minecraft
cp -r ./data ./data-backup

Update configuration

environment:
  TYPE: FABRIC  # Changed from VANILLA
  VERSION: "1.20.4"
  MODRINTH_PROJECTS: |
    fabric-api

Start server

docker-compose up -d

Your vanilla world will work with Fabric.

Players will need to install Fabric and your server’s mods on their clients to connect.

Next Steps

Modrinth Integration

Auto-download mods from Modrinth

CurseForge Mods

Install CurseForge modpacks

Quilt Server

Try Quilt, a Fabric fork with enhancements

Hybrid Servers

Run Fabric mods with plugins

Get Started

Server Types

Mod Platforms

Configuration

Mods & Plugins

Versions

Operations

Deployment

Advanced

​Overview

​Configuration

​Basic Setup

​Version Selection

​Automatic Latest Versions

​Specific Loader Version

​Specific Launcher Version

​Environment Variables

​Installing Fabric API

​Mod Management

​Manual Mod Installation

​Auto-Download from Modrinth

​Auto-Download from CurseForge

​Popular Fabric Mods

​Performance Optimization

​Server Administration

​Quality of Life

​Advanced Configuration

​Custom Fabric Launcher

​Custom Meta API

​Force Reinstall

​Complete Production Example

​Mod Configuration

​Config Files

​Server-Side vs Client-Side Mods

​Performance Tuning

​Recommended Mods for Performance

​Memory Allocation

​Troubleshooting

​Corrupted Launcher

​Mod Compatibility Issues

​Version Mismatch

​Migration Guide

​From Vanilla to Fabric

​Next Steps

Modrinth Integration

CurseForge Mods

Quilt Server

Hybrid Servers

Build docs developers (and LLMs) love

Overview

Configuration

Basic Setup

Version Selection

Automatic Latest Versions

Specific Loader Version

Specific Launcher Version

Environment Variables

Installing Fabric API

Mod Management

Manual Mod Installation

Auto-Download from Modrinth

Auto-Download from CurseForge

Popular Fabric Mods

Performance Optimization

Server Administration

Quality of Life

Advanced Configuration

Custom Fabric Launcher

Custom Meta API

Force Reinstall

Complete Production Example

Mod Configuration

Config Files

Server-Side vs Client-Side Mods

Performance Tuning

Recommended Mods for Performance

Memory Allocation

Troubleshooting

Corrupted Launcher

Mod Compatibility Issues

Version Mismatch

Migration Guide

From Vanilla to Fabric

Next Steps