Configuring PAS for OpenEdge for Tomcat load balancing
Configuring PAS for OpenEdge to enable Tomcat load balancing involves:
1. Creating an instance (lb) that is dedicated to load balancing.
You can use the TCMAN create action to instantiate an instance that must be named either lb or jklb. No other configuration is required, but note that you should not deploy any Web applications to the lb instance.
2. Optionally creating an instance (status) to gather metrics on the instances in the load balancing group.
You can use the TCMAN create action to instantiate an instance that must be named status or jkstatus. No other configuration is required, but note that you should not deploy any Web applications to the status instance.
Also note that the lb automatically keeps track of the runtime status of instances in its load balancing group. It will not forward a request to an instance that has crashed or is not running for some other reason. Therefore, the status instance is only required if you want to monitor performance data about the instances in the load balancing group.
3. Generating and deploying a worker.properties file.
The worker.properties file is a Tomcat feature that defines the load balancing instance (lb), the status instance , and the instances that handle requests status.
You can create a preliminary worker.properties file using the TCMAN (or PASMAN)workers action. The action gathers information on all instances registered to the local PAS for OpenEdge core server (CATALINA_HOME). Note that there must be an instance named lb or jklb that will function as the load balancer.
The workers action only includes local instances. If you have instances on multiple machines, you must:
a. Run the TCMAN workers action on each machine.
b. Combine the workers.properties file from each machine into a single workers.properties file.
c. Comment out the workers.common.host property.
d. Add a workers.instance_name.host=host_name property to each instance.
The TCMAN workers action references the content of the $CATALINA_HOME/extras/workers.template file when it builds a preliminary worker.properties file. You can modify the workers.template file to include settings that are typical in your local configuration.
The preliminary worker.properties is created in the temp directory of the CATALINA_HOME server (for example, $DLC/servers/pasoe/temp). Use this file as a starting point; you may need to modify parameter values to better suit your particular application configuration.
The TCMAN workers action references the content of the $CATALINA_HOME/extras/workers.template file when it builds a preliminary worker.properties file. You can modify the workers.template file to include settings that are typical in your local configuration.