Installing a Minecraft server on FreeNAS

Learn how to install a Minecraft server on your FreeNAS server. Configure your installation as a service that starts every time the jail starts.

A Minecraft server allows you to play with friends in the same virtual world. The server keeps track of the state of the environment as users join and leave the world.

Note: The instructions in this tutorial install Minecraft: Java Edition server, which is only compatible with Minecraft: Java Edition.

Preparing the jail

The instructions in this post host the app server in a jail on FreeBSD. To learn why we use jails for this purpose, check the Application server section of our self-hosted architecture post.

In this section, you’ll perform the following tasks:

Create a jail.
Configure networking on the jail.
Install the prerequisite packages.

Run the commands from a session in your FreeBSD host.

To create a jail:

Fetch or update the release version of FreeBSD for jail usage:
```
iocage fetch --release 11.3-RELEASE
```

Create a jail named minecraft:

iocage create --name minecraft --release 11.3-RELEASE

To configure networking on the jail:

Configure the IP address. The following example sets the IP address to 192.168.1.123 using a subnet mask of 24 bits on the em0 interface. The command uses the CIDR notation.
```
iocage set ip4_addr="em0|192.168.1.123/24" minecraft
```
Configure the default router. The following example sets the default router to 192.168.1.1:
```
iocage set defaultrouter=192.168.1.1 minecraft
```

Start the jail and open a session to complete the rest of the tasks in this section:

iocage start minecraft
iocage console minecraft

Install the openjdk8 and curl packages:

pkg update
pkg install --yes openjdk8 curl

Running the server for the first time

In this section, you’ll perform the following tasks:

Download the Minecraft server binaries.
Accept the Minecraft end user license agreement (EULA).
Start the server.

To download the Minecraft server binaries:

Check the Minecraft server download page and copy the link to the minecraft_server.x.xx.x.jar file.
Open a session on the jail:
```
iocage console minecraft
```

Create a folder to store the server files:

mkdir -p /root/minecraft
cd /root/minecraft

Use curl to download the server binaries. Replace the URL in the following example with the URL from the first step in this procedure:
```
curl -O https://launcher.mojang.com/v1/objects/3dc3d84a581f14691199cf6831b71ed1296a9fdf/server.jar
```

To accept the Minecraft EULA:

Run the following command:

java -jar /root/minecraft/server.jar

The command prints a the following message:

 [main/ERROR]: Failed to load properties from file: server.properties
 [main/WARN]:  Failed to load eula.txt
 [main/INFO]:  You need to agree to the EULA in order to run the server.
               Go to eula.txt for more info.

The previous command creates a set of files, including eula.txt. Make sure that you agree with the Minecraft EULA, open eula.txt, and replace eula=false with eula=true. You can also replace the previous text by using the following command:
```
sed -i .bak 's/eula=false/eula=true/g' /root/minecraft/eula.txt
```

To start the server for the first time, run the following command, which includes the options:

Xms512M: Sets the initial Java heap size to 512MB.
Xmx1024M: Sets the maximum Java heap size to 1024MB.
nogui: Starts the server without a graphical user interface.

java -Xms512M -Xmx1024M -jar /root/minecraft/server.jar nogui

The command displays the following output:

[Server thread/INFO]: Starting minecraft server version 1.14.4
[Server thread/INFO]: Loading properties
[Server thread/INFO]: Default game type: SURVIVAL
[Server thread/INFO]: Generating keypair
[Server thread/INFO]: Starting Minecraft server on *:25565
[Server thread/INFO]: Using default channel type
[Server thread/INFO]: Preparing level "world"
[Server thread/INFO]: Found new data pack vanilla, loading it automatically
[Server thread/INFO]: Reloading ResourceManager: Default
[Server thread/INFO]: Loaded 6 recipes
[Server thread/INFO]: Loaded 811 advancements
[Server thread/INFO]: Preparing start region for dimension minecraft:overworld
[Server-Worker-6/INFO]: Preparing spawn area: 0%
[Server-Worker-5/INFO]: Preparing spawn area: 1%
[Server-Worker-3/INFO]: Preparing spawn area: 2%
...
...
[Server-Worker-7/INFO]: Preparing spawn area: 92%
[Server-Worker-2/INFO]: Preparing spawn area: 97%
[Server thread/INFO]: Done! For help, type "help"

In the previous example, the server starts on port 25565, which is the default port of the Minecraft server. You’ll need this information in the next section. Your server is ready and waiting for clients to connect.

Connecting a Minecraft client

To test the Minecraft server, connect a Minecraft: Java Edition client. Run the following procedure from your client computer:

Download and install the Minecraft: Java Edition client by following the instructions on the Minecraft download page.
Start Minecraft: Java Edition and click Play.
In the start screen, click Multiplayer.
In the Play Multiplayer screen, click Add Server.
In the Edit Server Info screen, type the IP address and port of your server in the Server Address field. For example, our instructions use the address 192.168.1.123:25565.
Back in the Play Multiplayer screen, select the new server and click Join Server.

Your client joins the game and the server displays the following output:

[User Authenticator #1/INFO]: UUID of player USERNAME is ...
...
[Server thread/INFO]: USERNAME joined the game

You have successfully installed a Minecraft server on FreeNAS. However, the server is running in an interactive session on the jail, which means that the server stops if you close your shell. The next section explains how to run the server without an interactive session.

Configuring the server as a daemon service

You can configure the Minecraft server to run as a service on the jail, which allows you to start the service whenever the jail starts. You don’t need to open a session nor run the Java command.

To configure the service:

Open a session on the jail:
```
iocage console minecraft
```
If it doesn’t exist, create the rc.d folder to store the service script:
```
mkdir -p /usr/local/etc/rc.d
```

Save the following script in the /usr/local/etc/rc.d/minecraftd file:

#!/bin/sh
#
# PROVIDE: minecraftd
# REQUIRE: LOGIN DAEMON NETWORKING mountcritlocal
# KEYWORD: shutdown
#
# Use the following variables to configure the minecraft server. For example, to
# configure the ON/OFF knob variable:
# sysrc minecraftd_enable="YES"
#
# minecraftd_enable="YES"
# minecraftd_user_dir="/root/minecraft"
# minecraftd_jar_path="/root/minecraft/server.jar"
# minecraftd_java_opts="-Xms512M -Xmx1024M"

. /etc/rc.subr

name=minecraftd
rcvar=`set_rcvar`
pidfile=/var/run/minecraftd.pid

load_rc_config $name

start_cmd="${name}_start"
stop_cmd="${name}_stop"
status_cmd="${name}_status"

: ${minecraftd_enable="NO"}
: ${minecraftd_user_dir="/root/minecraft"}
: ${minecraftd_jar_path="/root/minecraft/server.jar"}
: ${minecraftd_java_opts="-Xms512M -Xmx1024M"}

minecraftd_start() {
    if [ -e $pidfile ]; then
        echo "$name already running."
    else
        echo "Starting $name..."
        cd "$minecraftd_user_dir"
        /usr/sbin/daemon -f -p $pidfile \
            /usr/local/bin/java $minecraftd_java_opts \
            -jar $minecraftd_jar_path nogui
        echo "$name started."
    fi
}

minecraftd_stop() {
    if [ -e $pidfile ]; then
        echo "Stopping $name..."
        cat $pidfile | xargs kill
        echo "Stopped."
    else
        echo "$name is not running."
    fi
}

minecraftd_status() {
    if [ -e $pidfile ]; then
        echo "$name is running."
    else
        echo "$name is not running."
    fi
}

run_rc_command $1

Provide execute permissions to the script:

chmod +x /usr/local/etc/rc.d/minecraftd

Configure the service to start when the jail starts:
```
sysrc minecraftd_enable="YES"
```
Exit the jail session:
```
exit
```
Restart the jail:
```
iocage restart minecraft
```

Connect your Minecraft client again. You can use the same server configuration from the Connecting a Minecraft client section.