5.3

Table Of Contents

38 vFabric Web Server

Configuring vFabric Web Server

Instances

• The loadfactor parameter specifies how much load a particular member carries. If you want each member to carry

the same load, set the numbers equal to each other (as in the example above). If, however, you want one member to work

three times harder than the other, set the load factors to 3 and 1.

• Use the lbmethod parameter of the ProxySet directive to specify the load balancing algorithm. The possible values

are as follows:

• byrequests: performs weighted request counting. This is the default value.

• bytraffic: performs weighted traffic byte count balancing.

• bybusyness: performs pending request balancing.

• Use the ProxyPass and ProxyPassReverse to specify the context URLs of the application that will be routed to

the tc Runtime instances that you have configured in the load balancing scheme. ProxyPass specifies that when the

vFabric Web Server instance receives a request at the /my-app URL, it routes the request to the load balancer that will

in turn route it to the tc Runtime instance. ProxyPassReverse does the reverse: when the tc Runtime instance sends a

response to a user who is using /my-app, the response appears to come from the vFabric Web Server instance, and not

the tc Runtime instance. Thus the details of the tc Runtime instance are hidden from the user.

4. Optional. If you want to enable the balancer manager Web application to watch the load balancing activity and control the

behavior, add the following to the httpd.conf configuration file of your vFabric Web Server instance:

SetHandler balancer-manager

Order Deny,Allow

Deny from all

# BE VERY RESTRICTIVE with YOUR ALLOW STATEMENT

Allow from 127.0.0.1

</Location>

5. Optional. If you want to enable sticky sessions, follow these steps:

a. In the httpd.conf file of the vFabric Web Server instance, update the ProxySet directive of the <Proxy>

element you configured in a preceding step by adding the stickysession=JSESSIONID|jsessionid

parameter. This parameter configures the cookie/path that will be used for stickiness. For example (update shown in

bold):

BalancerMember http://192.168.0.203:8081 route=instanceOne loadfactor=1

BalancerMember http://192.168.0.203:8082 route=instanceTwo loadfactor=1

ProxySet lbmethod=byrequests stickysession=JSESSIONID|jsessionid

</Proxy>

b. Go to the computer on which vFabric tc Server is running and update the server.xml configuration file of

both tc Runtime instances by adding the jvmRoute=value attribute to the Catalina <Engine> element. Set

the value of this attribute equal to the value you specified (in a preceding step) for the route parameter of the

BalancerMember directive in the vFabric Web Server httpd.conf file that describes the tc Runtime instance.

Following our example, the updated <Engine> entry for the instanceOne tc Runtime instance (that uses port

8081) would be as follows (new attribute in bold):

If you configure sticky sessions, VMware recommends that you also configure session replication for the tc Runtime

instances. For details, see the section titled Enabling Clustering for High Availability in the vFabric tc Server

documentation.

6. Start the vFabric Web Server instance. Following our example: