Apache 1.3.x and 2.0.x

Apache HTTP Server versions 1.3.x and 2.0.x provide load balancing by using mod_rewrite Apache module.

Refer to the following:

All configurations examples explained here work on both Apache version 1.3.x and 2.0.x

Sessionless requests

The following example shows how to configure the Apache mod_proxy module to do load balancing for sessionless requests. It assumes the architecture illustrated by the sample architecture 1.
# Apache configuration file
<IfModule mod_rewrite.c>

RewriteEngine on

RewriteMap servers rnd:hosts.txt

RewriteRule ^/(.*) http://${servers:host}/$1 [P,L] 

</IfModule>

For example, the http://localhost/ws/r/echo URL will be rewritten to http://GAS1.corporate.com/ws/r/echo, assuming that the GAS1.corporate.com server has been chosen.

Session-bound requests

The following example shows how to configure the Apache mod_proxy module to do load balancing for session-bound requests. It assumes the architecture illustrated by the sample architecture 2. The example illustrates path-based session-bound request routing.
# Apache configuration file
<IfModule mod_rewrite.c>

RewriteEngine on

RewriteMap servers rnd:vdirs.txt

RewriteRule ^/gas/(.*) /${servers:vdir}/$1
RewriteRule ^/GAS1/(.*) http://GAS1.corporate.com/GAS1/$1 [P,L]
RewriteRule ^/GAS2/(.*) http://GAS2.corporate.com/GAS2/$1 [P,L]

</IfModule>

For example, the http://localhost/gas/wa/r/gwc-demo URL will be rewritten to http://localhost/GAS2/wa/r/gwc-demo, assuming that the servers:vdir variable contains GAS2 at this time, then will be rewritten to http://GAS2.corporate.com/GAS2/wa/r/gwc-demo. Likewise, the http://localhost/GAS2/wa/sua/93837374/1 URL will be rewritten to http://GAS2.corporate.com/GAS2/wa/sua/93837374/1.