How To Install Garry's Mod Server on CentOS 7

In this tutorial, I will explain how to setup a Garry's Mod server. This tutorial was written for CentOS 7.

##Prerequisites

Let's make sure that the system is fully updated. Create a new user for this server, and be sure to use a strong password.

yum update
yum upgrade -y
adduser gmod
passwd gmod

Open the required firewall ports with firewall-cmd.

firewall-cmd --zone=public --add-port=27015/tcp --permanent
firewall-cmd --zone=public --add-port=27015/udp --permanent
firewall-cmd --reload

Install the required system libraries to run SteamCMD.

yum install glibc.i686 libstdc++.i686 -y

Now, switch to the user that was just created.

su gmod
cd ~

Download SteamCMD by using wget.

wget https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz
tar xf steamcmd_linux.tar.gz

Install the game server files with SteamCMD.

./steamcmd.sh +login anonymous +force_install_dir ./gmod +app_update 4020 validate +quit

When it says Success! App '4020' fully installed., simply type quit and press enter.

The game server is now installed.

##Customizing the server

To change the name of your server, edit the server.cfg file.

nano ~/gmod/garrysmod/cfg/server.cfg

Paste the following into server.cfg and change ServerName and RconPassword to anything you would like.

hostname "ServerName"
rcon_password RconPassword

##Updating your server

We will create a script so that you can update your server with a single command. First, create the file update_gmod.txt.

nano /home/gmod/update_gmod.txt

Paste in the following:

login anonymous
force_install_dir ./gmod
app_update 4020
quit

To update your server, you just need to run the following command:

cd ~
./steamcmd.sh +runscript update_gmod.txt

##Running your server Navigate to the gmod folder and run your server.

cd /home/gmod/gmod/
screen -dmS gmod ./srcds_run -game garrysmod -console -port 27015 +maxplayers 18 -tickrate 66 +map gm_flatgrass

At this point, your server is now running in the background. You may shut it down at anytime with the following command.

screen -S gmod -X quit

Enjoy your new Garry's Mod server!