Configuring Workers for Load Balancing

A Tomcat worker is a Tomcat instance that runs behind a web server such as Apache. The web server forwards the servlet requests to the worker and the worker executes the servlets or any other content on behalf of the web server.

In a clustered OneData environment, you must configure a load balancer worker and multiple Tomcat workers to distribute the requests between them. A load balancer is a worker that does not directly communicate with Tomcat. Instead, it manages several real workers, called members or sub workers of the load balancer. You can configure the workers for the Tomcat web server plug-in by defining them in the workers.properties file.

For more information about creating a workers.properties file and its location, see the following task to configure the workers. If you are configuring the workers for the first time, follow these steps. Otherwise, see Adding a OneData Instance to the Cluster.

Note:

This task describes how to configure two workers and a load balancer worker. You can configure as many workers as required in your cluster environment based on these steps.

1. In the load balancer machine, open a text editor. Copy and paste the following configuration details to create a worker.properties file.

# Define 1 real worker using ajp13
worker.list=balancer
worker.balancer.type=lb
worker.balancer.balance_workers=worker1,worker2
worker.balancer.method=B

# Set properties for worker1 (ajp13)
worker.worker1.type=ajp13
worker.worker1.host=<Host IP>
worker.worker1.port=<AJP Port>|
worker.worker1.lbfactor=1

# Set properties for worker2 (ajp13)
worker.worker2.type=ajp13
worker.worker2.host=<Host IP>
worker.worker2.port=<AJP Port>
worker.worker2.lbfactor=1

2. You must change the values for <Host IP> and <AJP Port> in the above configuration based on the clustering you want to set up.

<Host IP> is the IP address of the cluster node in which the OneData instance is installed and <AJP Port> is the port used by the load balancer to communicate with a OneData instance.

Important:

balancer, worker1 and worker2 are the worker names that you can choose. You must use the same worker names in all the configurations.

3. Save the file as workers.properties in the same folder as the httpd.conf file is. Typically, this is in the folder apache_server_root\conf.

LoadModule lbmethod_byrequests_module modules/mod_lbmethod_byrequests.soLoadModule slotmem_shm_module modules/mod_slotmem_shm.so LoadModule proxy_module modules/mod_proxy.soLoadModule proxy_ajp_module modules/mod_proxy_ajp.soLoadModule proxy_balancer_module modules/mod_proxy_balancer.so

<Proxy balancer://onedatacluster stickysession=JSESSIONID>BalancerMember ajp://<Apache http server IP>:<AJP-Port1> min=10 max=100 route=node1 loadfactor=1 BalancerMember ajp://<Apache http server IP>:<AJP-Port2> min=20 max=200 route=node2 loadfactor=1</Proxy>ProxyPass /onedata balancer://onedatacluster/onedata<Location /balancer-manager>SetHandler balancer-manager</Location>

5. Start apache in a DOS box by typing httpd.exe and type httpd.exe -k install to install as a service.