Clustering J2Ee Agents; Prerequisites; Creating A Cluster Configuration - Novell ACCESS MANAGER 3.1 SP1 - AGENT GUIDE Manual

Clustering J2EE Agents

3
The J2EE Agents can be clustered to provide load balancing and fault tolerance. If the agent where
the user's session was established goes down, the user's request is sent to another agent in the
cluster. This agent pulls the user's session information from the Identity Server. This allows the user
to continue accessing resources, without needing to reauthenticate.
A cluster of J2EE Agents must reside behind a Layer 4 (L4) server. Clients access the virtual IP on
the L4, and the L4 alleviates server load by balancing traffic across the cluster of agents. Whenever
a user enters the URL for an agent resource, the request is routed to the L4 server, and L4 routes the
user to one of the agents in the cluster, as traffic necessitates.
A cluster is created by assigning one or more agents to a cluster configuration. The agents must all
belong to one type. For example, you can have a cluster of WebLogic agents, but not a cluster with
both JBoss agents and WebLogic agents.
Section 3.1, "Prerequisites," on page 63
Section 3.2, "Creating a Cluster Configuration," on page 63
Section 3.3, "Assigning a J2EE Agent to a Cluster," on page 64
Section 3.4, "Modifying Cluster Details," on page 65
Section 3.5, "Removing a J2EE Agent from a Cluster," on page 65

3.1 Prerequisites

An L4 switch installed. You can use the same switch for clustering all Access Manager devices.
The LB algorithm of the L4 switch can be anything (hash/sticky bit), defined at the Real server
level.
Persistence (sticky) sessions enabled on the L4 server. You usually define this at the virtual
server level.
One or more Agents installed. They must all be of one type.
The base URL DNS name of this configuration must be the virtual IP address of the L4 server.
The L4 balances the load between the J2EE Agents in the cluster.
The application server on which the J2EE Agents reside must support clustering.
Your DNS server must to be configured to resolve the base URL of the agent cluster to the L4
switch.

3.2 Creating a Cluster Configuration

To create a new cluster of J2EE Agents:
1 In the Administration Console, click Devices > J2EE Agents.
2 Select the J2EE Agent that you want to add to the cluster, then click New Cluster.
The New Cluster dialog box appears.
3
Clustering J2EE Agents 63