Tomcat load balancing is achieved by designating a PAS for OpenEdge instance that only refers requests from a web server to instances that can process them. Tomcat is built into PAS for OpenEdge. The following figure show this load balancing configuration.

Tomcat load balancing

Some advantages of this configuration, compared to Apache proxy host load balancing, are:

  • The PAS for OpenEdge instance that is designated as a load balancer (lb in the figure) is aware of the run-time status of each instance in its group and will not forward a request to an instance that is down.
  • Tomcat load balancing allows you to configure a PAS for OpenEdge instance as as a monitor of run-time statistics for each instance in the load balancing group (the status instance in the figure).