Java Grid Computing

PCQLinux 2005 comes with a built-in grid-computing software 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 and sends back the results to it. And finally the Client splits the jobs to collect the job results. 

A minimum of three machines running PCQLinux 2005 are needed-one will run the JCGrid Server, the second will act as the Worker and the third as your Client to run the job process. To increase the computing power, you can add as many worker machines to the set up. To set up the JCGrid, first set up your server machine. Boot the machine with the PCQLinux 2005 CD and select the 'Advanced Install>Grid Computing' install type. For installing the Worker and Clients' 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 and assign them a fixed IP. In our case, we assigned 192.168.3.1 to the Server, 192.168.3.2 to the Worker and 192.168.3.3 to the Client machines. 

The grid computing setup also supports PoVRay (Persistence of Vision Raytracer)-a real-time light rendering engine. 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. 

Configuring JCGrid Worker 





Open a terminal window from the GUI and CD (Change Directory) to /opt/jcgrid-worker and open povray-worker-go.sh file in a text editor. Then set the variable JCGRID_SERVER_NAME with the IP address of the JCGrid Server (in our case the IP was 192.168.3.1). In the same file also 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 this command.

# services iptables stop

With this your grid computing setup is ready to process the jobs. 

Running jobs on the grid





Processing and rendering PoVRay graphics takes lesser time with JCGrid. 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-client-go.sh cornell demos/povray/cornell 320 240 64"

The script takes a PoVRay graphics file called 'cornell' and renders it at the resolution of 320 x 240 with 64-color depth.