Load-Balancing

Load Balancing with Weighted Round Robin (WRR) and Least Connection First (LCF).

Running the example

The ant-buildfile is just a demonstration on how the load-balancer can be used. Command-line parameters to the individual targets must be configured manually in the build-file!

Add More Servers:

To add more servers simply add some more entries s to the 'run-servers' target. These are the port numbers to start the servers on.

<arg value="9000"/> // port to start a server on
<arg value="9001"/>
<arg value="9002"/>

Different Load-Balancer Config:

To change the load-balancer configuration best edit the 'config.xml'-file in the root directory. Consult the example files 'examples/lcf.xml' and 'examples/wrr.xml' for how to configure the balancer for different algorithms.

<?xml version="1.0"?>
<loadbalancing>
    <strategyname>LCF</strategyname>        // LCF or WRR
    <slave>
        <url>http://localhost:9000</url>    // exchange port number for different client
        <weight>30</weight>                 // add only if algorithm is WRR
    </slave>
    <slave>
        <url>http://localhost:9001</url>
        <weight>50</weight>                 // add only if algorithm is WRR
    </slave>
</loadbalancing>

Different Client Config:

The client can also be configured in the build-file. Simply change the values in the 'run-client' target.

<arg value="Gary"/>                                         // Client name; important for session persistence
<arg value="http://localhost:5000/RPC2"/>                   // URL of load-balancer
<arg value="A quick brown fox jumps over the lazy dog"/>    // request to send

Different Server Types:

If you want to use CPU-, RAM- or IOServers instead of standard SlaveServers the easiest way is to edit the tag in the 'run-servers' target. Port configuration works exactly the same.

// classname = "loadbalancing.slave.SlaveServer|IOServer|RAMServer|CPUServer
<java classname="loadbalancing.slave.SlaveServer" ...

Example Run:

/* run the balancer with default configuration */
> Terminal1:    ant run-servers
> Terminal2:    ant run-loadbalancer
> Terminal3:    ant run-client
> Terminal4:    ant run-client
...

Note that requests to SlaveServers (default) need 30s for better load-balancing demonstration!