>This is actually very easy with the existing code and a tiny patch I >submitted a few weeks ago. We're using it in production mode, so it is >known to be stable. The first version I submitted had some additional >logging added, but I'm attaching a minimal patch. > >All you have to do is set the lbfactor in workers.properties to 0, and >it should never select that worker unless the session route points to >it, or the primary worker is down. Exactly what we want :) >This also has the added benefit of making externally load balanced >clusters behave properly for AOL/Compuserve users without special >configuration of the load balancer. Those services use IP randomizing >proxies which break generic IP-based sticky. This will cause the >sessions to be re-routed from the Apache that receives the request to >the Tomcat that initiated the session. This actually works, because we >were able to remove all of our special configurations to deal with this >from our load balancers. The problem is described at >http://webmaster.info.aol.com/index.cfm?article=15 >This patch changes the behavior by pre-initializing lb_value for each >worker. The selection algorithm searches for the worker with >the lowest >lb_value that is not in a failed state. It then increments >the lb_value >by the lb_factor. lb_factor is set to the inverse (1/x) of the >lb_factor specified in the config file. When lb_factor in the config >file is 0, this number becomes basically MAX_DOUBLE. That means that >lb_value becomes MAX_DOUBLE, so it will never be selected for any >practical purposes. > >This patch has been tested extensivly in production use, and works >perfectly. Seems fine to me. I'll commit it today :)
