I have a web app that is going to run on multiple servers. I'd like to make sure, that requests using the same session (HTTP cookie header with value JSESSIONID=x) always communicate with the same server. That is, until the session "moves" to a different server in certain circumstances (not only when the server fails, but also due to some server side caching and performance strategies).
My web app works well with that scenario, but what kind of load balancer should I use? Obviously, I could load balance on application level, but I'm looking for something more efficient. Maybe specialized hardware (maybe not)? I can't spend a lot of money...
Thanks for your answers so far: I found out now, that Pound and HAProxy can be configured to look for certain cookies. I couldn't find out yet, if they also allow to update the mapping dynamically (when the session "moves" to a different app server)?
And are there (inexpensive) hardware solutions, which can do that, too? (Would that cost less than an extra load balancing server?)