JBoss.org Community Documentation

15.1. Stateless Session Bean in EJB 2.x

Clustering stateless session beans is most probably the easiest case: as no state is involved, calls can be load-balanced on any participating node (i.e. any node that has this specific bean deployed) of the cluster. To make a bean clustered, you need to modify its jboss.xml descriptor to contain a <clustered> tag.



The <clustered>True</clustered> element is really just an alias for the <configuration-name>Clustered Stateless SessionBean</configuration-name> element in the conf/standard-jboss.xml file.

In the bean configuration, only the <clustered> element is mandatory. It indicates that the bean needs to support clustering features. The <cluster-config> element is optional and the default values of its attributes are indicated in the sample configuration above. Below is a description of the attributes in the <cluster-config> element..

  • partition-name specifies the name of the cluster the bean participates in. The default value is DefaultPartition. The default partition name can also be set system-wide using the jboss.partition.name system property.

  • home-load-balance-policy indicates the class to be used by the home stub to balance calls made on the nodes of the cluster. By default, the proxy will load-balance calls in a RoundRobin fashion. You can also implement your own load-balance policy class or use the class FirstAvailable that persists to use the first node available that it meets until it fails.

  • bean-load-balance-policy Indicates the class to be used by the bean stub to balance calls made on the nodes of the cluster. Comments made for the home-load-balance-policy attribute also apply.