Route requests across clusters on IBM i
The HTTP Server plug-is that comes with IBM WebSphere Application Server is typically used to balance requests for applications across members of the cluster. We can also use the On Demand Router (ODR) in dynamic, multicluster environments for routing. While an application can be mapped to more than one cluster, automatic plug-in generation does not provide routing or balancing traffic for the same application across multiple clusters. Multiple cluster environments with shared applications therefore cannot rely solely on WAS automatic plug-in generation to be able to route requests using a web server. One option in this scenario is developing a customized method for defining and maintaining the plug-in configuration file used by the web server to provide for the required routing of user requests.An important consideration in a multiple cluster environment is ensuring that all subsequent HTTP requests for a user are routed to the same cluster that processed the first HTTP request. The WebSphere Portal login processing depends upon preserving this cluster affinity during this initial time until the user has successfully logged in and session cookies maintain affinity. To guarantee that affinity is preserved during login, set the Navigator Service public.session parameter to a value of true; you should also set this parameter to true if we are using an ODR. Refer to "Portal Configuration Services" for information on how to configure this parameter.