Grid Computing with PCQLinux

Grid computing is form of distributed computing that uses

unused processing cycles of computers in a network for solving problems too

intensive for any one machine. PCQLinux 2006 comes with a grid-computing

solution called JCGrid (Java Grid computing). It has three components-JCGrid

server, worker and client. The server receives job requests from clients and

forwards them to the worker. The worker processes the requests. The client

splits the jobs into multiple requests.

Setup



A minimum of three machines running PCQLinux 2006 is needed for setting up a

grid-one will run the JCGrid Server, the second will act as the worker and the

third as your client. To set up the JCGrid, first set up your server machine.

Boot the machine with the PCQLinux 2006 CD and select the 'Advanced

Install>Grid Computing' install type. For installing the worker and client

machines, you need to do the same thing as mentioned above. Now you need to

configure the JCGrid. Connect all grid machines to the switch or hub (preferably

switch) and assign them a fixed IP. For this discussion, we assign 192.168.3.78

to the Server, 192.168.3.79 to the worker and 192.168.3.80 to the client.

If you want to set up DHCP instead, open /etc/dhcpd.conf in

a text editor and change the following entries :

ddns-update-style                                  



none;







default-lease-time                                   



21600;







max-lease-time                                      



21600;



option subnet-mask                                



255.255.255.0;







option broadcast-address                        


192.168.3.255;









option option-128 code 128 = string;







option option-129 code 129 = text;







subnet  192.168.3.0 netmask
255.255.255.0 { 







        range
dynamic-bootp          



192.168.3.10 192.168.3.253;       



# <-- DHCP IP Ranage







      



}

JCGrid client and it is currently using one server, two worker machine and one client machine.

Save this file and issue the command 'service dhcpd

restart” This will start the DHCP server on the Grid Computing server. The

grid setup also includes grid enabled PoVRay (Persistence of Vision Raytracer).

This is installed by default when you select this option. It is used as the

example in this article.

Configuring JCGrid Server 



Go to the server machine and open a terminal window in the GUI and issue the
following commands.

# services iptables stop



# cd /opt/jcgrid-server


# sh povray-server-go.sh&

This starts JCGrid Server as a background process. In case

of an error, check the error messages, and then check jcgrid-server.log in /opt/jcgrid-server

directory to understand what went wrong.

Configuring JCGrid Worker 



Open a terminal window from the GUI, change directory to /opt/jcgrid-worker and
open povray-worker-go.sh file in a text editor. Here, set the variable

JCGRID_SERVER_NAME with the IP address of the JCGrid Server (in our case the IP

was 192.168.3.78). Now, set the variable JCGRID_WORKER_NAME with a unique name

(Note: you can't have multiple workers with the same name). Save this file and

execute the script as mentioned below.

# services iptables stop







#cd /opt/jcgrid-worker







# sh povray-worker-go.sh&

Configuring JCGrid Client



Open a terminal window in the Client machine, go to /opt/jcgrid-client

directory and open 'povray-client-go.sh' file in a text editor. Set the variable

JCGRID_SERVER_NAME with the IP address of the JCGrid Server and also set the

variable JCGRID_CLIENT_NAME with a unique name. Save this file and execute the

command '# services iptables stop'.

With this your grid computing setup is ready to process the

jobs.

Running jobs on the grid from the Client



To run jobs, from the client machine, open a terminal window and go to /opt/jcgrid-client

directory. Here, you can test the grid setup with the demo PoVRay graphics

files. To run the test job, execute '# sh povray-guiclient.go.sh'. This will

open three GUI interfaces JCGrid Client, JCGrid Server Settings and Rendering

setting. JCGrid client will show the output of the running rendering process.

The JCGrid server setting window will be used to configure the JCGrid server

settings and rendering setting interface is used to run the rendering process.

Now on the JCGrid Server setting set the IP address of the

machine running 'povray-server'. Then come to Rendering settings window and

in “Working directory “ text box, select the povray graphics files that you

want to render on the JCGrid cluster.

Now, keeping the rest of the settings as default, click on

Start button to start the rendering process.

On the JCGrid client interface you will see the image being

rendered slowly, as you connect more worker nodes in the cluster the rendering

process will become faster.