blog-ahmza-com/content/posts/minecraft-server-on-docker.md

---
title: Minecraft Server on Docker ⛏ 🐳
date: 2022-05-24T09:33:35+01:00
author: "ahmza"
draft: false
weight: 

tags: ["Games", "Docker", "ARM"]
description: "Ever wanted to build a Minecraft server in docker !! Start here"
canonicalURL: "https://blog.ahmza.com/Page%28/posts/minecraft-server-on-docker.md%29"

cover:
    image: "/webp/posts/mc-docker/feature-anim.webp" # image path/url
    alt: "Minecraft Loves Docker" # alt text
    caption: "<text>" # display caption under cover
    relative: false # when using page bundles set this to true
showtoc: true
searchHidden: false
---

## **Introduction**

Minecraft is a great game and when it comes to multiplayer, a dedicated
server is the way to go (here's why[^1]). Myself and a few others
recently decided to start playing this game again, and I took the
opportunity to deploy the server in my lab.

A Minecraft server does not require a ton of resources to run, However
from my experience the more resources you can throw at it the better,
especially when you start to introduce mods and more than a few players.

I run our server on my main PC within WSL and Docker. This allows me to
leverage the system resources in my PC 🦾 leaving the [Pi Cluster](https://blog.ahmza.com/posts/building-a-docker-swarm-with-pis/)
to handle the rest of the stuff in my lab. The only reason I opted to
go this route is that I don’t want our server to be limited by hardware
resources as well as the Minecraft server effecting the overall
performance of the Pis.

## **Prerequisites**

- Docker
- Docker Compose

## **Requirements**[^2]

#### **Minimum (1-5 Players)**

- Intel Pentium 4 or AMD Athlon based CPU
- 512 MB RAM
- 2 GB Storage space

#### **Recommended (10-15 Players)**

- Intel Core or AMD K8 based CPU
- 3 GB RAM
- 16 GB Storage Space

#### **Optimal (20+ Players)**

- Intel i5/i7 or AMD Ryzen 5/7 Based CPU
- 6 GB RAM
- 35 GB Storage Space

## **Building the Container**

Now we have the formalities sorted, we can get to work on creating the
docker container for Minecraft.

1. **Create a directory in which you will keep the Minecraft server files**
    - `mkdir minecraft-server`
    - `cd minecraft-server`

2. **Create an environment file to be used by the Docker Container**
    - The *.env* file allows us to specify variables which we can use
        across the build process.
    - `touch .env`
    -  Edit the file in a text editor, i.e. vim `vim .env`
        ```bash
        CONTAINER_NAME=minecraft-server
        SERVER_MEM=4096 #change this to your desired value (in MB)
        SERVER_JAR=minecraft_server.1.18.2.jar
        ```

3. **Create the docker-compose.yml file**
    - The *docker-compose.yml* file specifies the container that we
        want to build, outlining the build context (Dockerfile),
        setting the variables (from .env), configuring storage volumes
        for persistence as well as ports and the container name.
    - `touch docker-compose.yml`
    - Edit the file in a text editor[^3], I.e. vim `vim docker-compose.yml`
        ```bash
        version: "3"

        services:
            minecraft-server:
                build:
                    context: .
                    args:
                        SERVER_MEM: ${SERVER_MEM}
                        SERVER_JAR: ${SERVER_JAR}
                volumes:
                    - .server-data:/server
                ports:
                    - 25565:25565
                    - 25575:25575
                container_name: ${CONTAINER_NAME}
                restart: unless-stopped

        volumes:
            server-data:
        ```

4. **Create the Dockerfile file**
    - The Dockerfile builds the container. We take the 17-jre base
        image apply our variables change the working directory to
        /server and start the jar file, effectively starting the
        Minecraft server.
    - `touch Dockerfile`
    - Edit the file in a text editor, i.e. vim `vim Dockerfile`
        ```bash
        FROM eclipse-temurin:17-jre

        ARG SERVER_MEM
        ARG SERVER_JAR

        ENV SERVER_MEM=${SERVER_MEM}
        ENV SERVER_JAR=${SERVER_JAR}

        WORKDIR /server

        CMD echo "Minecraft Server is starting\n" && java -Xms128M -Xmx${SERVER_MEM}M -jar ${SERVER_JAR} nogui
        ```

## **Setup the Server files**

We’re almost there, just a few steps left !!

The curious among you may have realised when trying to start the
container that it fails with the error below:

```bash
Minecraft Server is starting

Error: Unable to access jarfile server.jar
```

This is because we have not downloaded the server jar file yet, that is
our next step.

1. **Navigate to one of the following sites:**[^4]	
    - [Vanilla Minecraft Server](https://www.minecraft.net/en-us/download/server) - instructions found here[^5]
    - [Fabric Mod loader server](https://fabricmc.net/use/server/) - instructions found here [^6]
2. **Create a folder in the Minecraft-server folder called .server-data**
    - `mkdir .server-data`
    - `cd .server-data`
3. **Download the jar file - This will depend on the option above so read the instructions**
4. **Go back to the root minecraft-server folder**
    - `cd ..`
5. **Run the container**
    - `docker compose up` (use CTRL+C to exit)
    - Once the server unpacks all the files you will see this:
        ```bash
        minecraft-server  | Starting net.minecraft.server.Main
        minecraft-server  | [18:05:50] [ServerMain/INFO]: You need to agree to the EULA in order to run the server. Go to eula.txt for more info.
        minecraft-server exited with code 0
        ```
7. **Accept the EULA**
    -  Go into the .server-data folder
        1. `cd .server-data`
    - Edit the file named eula.txt in a text editor i.e. vim `vim eula.txt`
        1. Simply change `eula=false` to `eula=true`
8. **While in the .server-data folder make any changes you want**
    - Some files to note in here are
        - **server.properties** - properties like  server name, game mode, world type etc…
        - **ops.json** - list of server operators (easier to set ingame)
        - **whitelist.json** - list of players allowed to join the server everyone else rejected access.
9. **Run the container**
    - `docker compose up -d` (the -d means detatched so we can run the server in the background)
    - `docker logs minecraft-server --follow` Will show us the progress of the server startup (to exit out of this do CTRL+C)
    - If you see something like the following then you’re a winner 🥳
        ```bash
        [18:17:01] [Server thread/INFO]: Time elapsed: 25529 ms
        [18:17:01] [Server thread/INFO]: Done (34.571s)! For help, type "help"
        ```


[^1]: Hosting your own dedicated server allows you to modify every aspect of the server as you see fit. I.E you can modify the server-properties, you can implement a whitelist not to mention being able to add any mods you want

[^2]: Requirements Gathered from here [https://minecraft.fandom.com/wiki/Server/Requirements/Dedicated#Unix\_.28Linux.2C\_BSD.2C\_macOS.29](https://minecraft.fandom.com/wiki/Server/Requirements/Dedicated#Unix_.28Linux.2C_BSD.2C_macOS.29)

[^3]: Yaml is very picky 😞 when it comes to formatting so if you encounter any errors double check your formatting !!

[^4]: I have left Forge out as it is a more involved process plus Fabric is better 😜

[^5]: Right click the green link that says something like minecraft_server.x.xx.x.jar and copy the link address 

    curl -o server.jar \<link you copied here\>

[^6]: Select the Minecraft version, Fabric Loader Version and the Installer Version of your choice. I tend to go with the latest.

    Copy the curl command under CLI download