Chapter 4. Overview

The JBoss HTTP Connector mod_cluster uses Apache as the proxy server.

The JBoss HTTP Connector mod_cluster creates a feedback network between the worker nodes and the proxy server. The mod_cluster service is deployed on each of the worker nodes. This service feeds real-time load information to the proxy server. The proxy server then makes intelligent decisions on where to allocate work, based on the current load on each worker node. This real-time adaptive load distribution results in increased optimization of resources.

The information that is reported by the worker nodes and the load-balancing policy used by the proxy are both customizable.

The JBoss HTTP Connector mod_cluster service deployed on the worker nodes relays application lifecycle events to the proxy server. This allows the server to dynamically update its routing table. When an application is undeployed on a node, the proxy server no longer routes traffic for that application to that node.

The proxy server can be configured to announce its presence via UDP multicast. New worker nodes discover the proxy server and add themselves to the load-balancing cluster automatically. This greatly reduces the configuration and maintenance needed. When UDP multicast is not available or is undesirable, worker nodes are configured with a static list of proxies.

The JBoss HTTP Connector mod_cluster can use HTTP, HTTPS, or Apache JServ Protocol (AJP) for communication between the proxy and the worker nodes.