GlassFish is an open-source implementation of the Java platform. It supports several technologies including, EJB, JPA, JSF, JMS, RMI, JSP, servlets and allows developers to create portable and scalable applications. It allows you to monitor all instances in a cluster from a single host. It is designed for failover, scalability, and load balancing.

Source: LXer – How to Configure GlassFish Cluster with Automatic Load Balancing