Difference between revisions of "Running Multiple Servers on a single Linux computer"

From Armagetron
m (missed a few instances)
(1. wrong directory, 2. don't clear it! we want to see the errors!)
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  # runs the actual server. By default, the binary is called armagetronad-dedicated and is located in the prefix/bin directory. In this example, it is in /opt/armagetronad/bin directory.
 
  # runs the actual server. By default, the binary is called armagetronad-dedicated and is located in the prefix/bin directory. In this example, it is in /opt/armagetronad/bin directory.
  /opt/armagetronad/armagetronad-dedicated --configdir /opt/armagetronad/servers/$1/settings --vardir /opt/armagetronad/servers/$1/var
+
  /opt/armagetronad/bin/armagetronad-dedicated --configdir /opt/armagetronad/servers/$1/settings --vardir /opt/armagetronad/servers/$1/var
 
   
 
   
 
  # Clear the display, and indicates that the server has crashed, and then, wait 5 seconds before to restart the server, allowing you to quit with CTRL-C
 
  # Clear the display, and indicates that the server has crashed, and then, wait 5 seconds before to restart the server, allowing you to quit with CTRL-C
clear
 
 
  echo "Server has crashed. It will restart immediately..., press CTRL-C to cancel"
 
  echo "Server has crashed. It will restart immediately..., press CTRL-C to cancel"
 
  sleep 5
 
  sleep 5

Revision as of 08:01, 18 January 2009

Introduction

If you like to experiment new settings, it might be that you come with a set of interesting servers. A shame if you cannot run them all at the same time. Here is how you can achieve this on a Linux server. Please refer to the lag and bandwidth chapters in the wiki before to run multiple servers. If you run too many, you might end with a very bad gameplay.

This chapter will present you an easy way to run multiple servers on a single Linux computer, using GNU screen.

Server installation

First of all, you have to install the Armagetron Advanced Dedicated Server from source, not using the provided install script. This will allow to manage at will the settings and var directories. To do so, download the latest source package, and untar it in a temporary folder. CD to that folder and run the following commands:

In the "configure" command, the prefix will be the application directory. I have choose to install it in /opt/armagetronad/. Make your own choice:

./configure --prefix=/opt/armagetronad/ --disable-glout --enable-automakedefaults --disable-sysinstall --disable-etc --disable-useradd --disable-initscripts

Then, compile and install:

make
make install

Now, armagetron advanced dedicated is installed in the /opt/armagetronad/ folder.

Preparing the servers

The tree

CD to /opt/armagetronad/

cd /opt/armagetronad/

Create the following subdirectories:

mkdir servers      'This folder will be used to store server configurations
mkdir logs         'This one will be used to save the server logs
mkdir scripts      'And this one will be used to same the scripts we will see below

We have now to create our servers. To do so, go to the servers directory you have created earlier, and for each server, create a subfolder with a one-word name for the server, and two subfolders: var and settings. For exemple:

cd /opt/armagetronad/servers

To create a server called server1:

mkdir server1
mkdir server1/settings
mkdir server1/var

then copy your config files in the settings subfolder.

You can then create a second server, and more...

mkdir server2
mkdir server2/settings
mkdir server2/var

and so on...

The setting files

For each server, do not forget to create a "server_info.cfg" file (search the wiki about it), and to change the port number. Port can be from 4534 to 4540, meaning you can safely run up to 7 servers on the same computer, depending obviously on the settings of each servers, and the bandwidth they need.

We assume that you know enough about Server Administration to understand the above explainations. This article is about Advanced Server Administration, isn't it ?


The scripts

Now you have to create the scripts to launch and log all your servers. To allow managing each server separately, we will use GNU Screen. GNU screen is a terminal window manager. If it is not install on your server, you can get it with the usual installation tool (yum install screen, apt get screen, etc...). Again... advanced.... We assume you know how to install applications on linux and therefore, we assume GNU screen has been installed

You have to create two scripts. The first one will run a server and start logging the window in which the server has started. The second one will execute the first one for each folder in the /opt/armagetronad/servers folder. It will create a window for each of them. Therefore, if you don't want a server to run, you will have to temporarily move the server folder out from the /opt/armagetronad/servers directory.

Save the scripts in the /opt/armagetronad/scripts directory. I use nano which is an easy text editor.

The server script

The first script will be called in this example: srv

nano /opt/armagetronad/scripts/srv 

That creates a text file called srv in the scripts directory. Write the following lines in the file:

#!/bin/bash

screen -S $1 -X logtstamp on 					# print timestamps in log file
screen -S $1 -X logfile /opt/armagetronad/$1_%d%m%Y-%c.log 	# create a logfile in the logs subfolder
screen -S $1 -X log on 					# Turn on logging for the server window
while true; do 						# start a loop to allow server restart if it crashes

# runs the actual server. By default, the binary is called armagetronad-dedicated and is located in the prefix/bin directory. In this example, it is in /opt/armagetronad/bin directory.
	/opt/armagetronad/bin/armagetronad-dedicated --configdir /opt/armagetronad/servers/$1/settings --vardir /opt/armagetronad/servers/$1/var 	

# Clear the display, and indicates that the server has crashed, and then, wait 5 seconds before to restart the server, allowing you to quit with CTRL-C
	echo "Server has crashed. It will restart immediately..., press CTRL-C to cancel"
	sleep 5

done # end the loop

To save the file, press CTRL-X and Y to confirm. You have now a file called srv in /opt/armagetronad/scripts.

the global script

Create the second script. I called it start: nano /opt/armagetronad/scripts/start

#!/bin/bash

# If you run the script with a parameter (server name), only that server will be start. Otherwise, all servers in the /opt/armagetronad/servers directory will be started

if [ "$1" != "" ]; then
	screen -S $1 -X quit				# Kill the window if it exists already, avoiding to run the same server twice
	screen -dmS $1 /opt/armagetronad/scripts/srv $1			# start a GNU screen window with the specified server inside
else
	for f in $(ls /opt/armagetronad/servers/.)				# start a loop running the following command for any existing folders in the /opt/armagetronad/servers folder
		do
			screen -S $f -X quit				# Kill the window if it exists already, avoiding to run the same server twice
			screen -dmS $f /opt/armagetronad/scripts/srv $f	# start a GNU screen window with the server inside for each server folder
		done							# ends the loop
fi

Save it and exit the same way as before.

Starting all servers

To make your servers start at boot, edit the /etc/rc.local file and add the "start" script at the end of /opt/armagetronad/scripts/start

If you want to manually start all servers, just run the ./start script.

Starting a single specific server

If you want to start (or restart) a single server, just run

./start servername

Server management

GNU screen

GNU screen is a great tool. As explained above, it allow a multi-windowed environement on the simple terminal. And even better, the windows stay alive, evening when you disconnect from the server. You can find everything about GNU screen by typing man screen on a terminal.


Listing the running servers

To see the existing windows, meaning here, the running servers, type screen -ls. It will gives you a list of running windows.

Accessing and leaving a server console

To attach to a window, type screen -r servername. You will be in the server console. You can then do all the command you would usually do there. Remote moderation, server adjustment, and so on.

To detach, but keep the server running, press CTRL-a d (control key + low case A, then low case D to detach). You can find all GNU screen key combinations by reading man screen.

Killing a server

To kill a server, attach to its window, and press CTRL-C. This will kill the script, and the window. Then press ESC to exit the dead window. An alternate way is to run

screen -S servername -X quit

This will kill and end the window and the server inside.

Log files

Everytime the srv script is run, a new logfile will be created in the /opt/armagetronad/logs folder. Keep an eye on log sizes. You don't want to run out of disk space because of Armagetron Advanced, do you ?

Test the server autorestart

If you want to try if the server restarts when it crash, do not press CTRL-C into the window. CTRL-C kill the script, therefore it will not be able to restart. Instead, run the quit command inside the server console. It will close the server, and you will be able to see the message, and the server restarting.

Credits

This article has been written by Superkikim. These scripts and setup details are used to run the "FAST TRACK" servers.