I want to setup a loadbalancer with 2 machines. The loadbalancer should reside on one machine and split load between itself and other machine (with a greater percentage of request hitting other machine). There is no issue of cookie and session, since every request is independent. Also I have given my client an IP address (something like http://188.8.131.52/aaa.php ) not a domain name so I want the request coming to that IP to be load balanced. Both my machines are VPS residing on linode. How do I configure apache mod proxy balancer(if its possible that way)?
HAProxy is great, I've used this quite a bit: http://haproxy.1wt.eu/
Pound is another one: http://linux.die.net/man/8/pound
I now use Zeus (With Joyent) and can't recommend it enough: http://www.zeus.com/products/load-balancer/index.html
As for mod_proxy, I wouldn't recommend it. But here is a tutorial if you'd still like to pursue it: http://wiki.apache.org/cocoon/LoadBalancingWithModProxy
I cannot speak for mod proxy balancer, but Linux Virtual Server will do everything you have asked for above.