Portal Server on an Application Server Cluster

This section describes how Application Server Enterprise Edition software, BEA WebLogic Server, and IBM WebSphere Application Server manage application server clustering. Application server clustering is a loosely coupled group of application servers that collaborate to provide shared access to the services that each server hosts. The cluster aims to balance resource requests, high availability of resources, and failover of application logic to provide scalability. Portal Server and Access Manager are not pure web applications. Instead, these applications are composed of local files residing on a machine and 17 default web applications. Many of the default web applications are portlets. The number of applications by default is:

• portal

• amserver

• ampassword

• amcommon

• amconsole

• search1

• psconsole

• communityportlets

• filesharing

• portletsamples

• ipc1

• ipc2

• rssportlet

• guessnumber

• wsssoportlet

• surveys

• wiki

The Java Enterprise System installs and configures the local files, configures the local application server, then deploys the WAR files on the local web application container. The WAR files themselves are not self-contained. The WAR files depend on the local files and directories on the machine to provide their service.

An application server cluster is a logical entity that groups many application server instances, potentially hosted on different machines. Pure web applications are deployed on a cluster using application server specific deployment tools. Once deployed on the cluster, the web applications are deployed to all the server instances that the cluster is made of, and managed in a central way.

Because of Portal Server’s dual nature, as a local application as well as a web application, install Portal Server on an application server using the following steps:

To Install Portal Server on an Application Server

1. Install Portal Server on all machines using the same configuration settings.

2. Deploy the web applications (portal, amserver, and psconsole . . .) to the cluster.

   The following sections explain what it means to enable Portal Server to run on an application server cluster.

Application Server Enterprise Edition

The Sun Java System Application Server Enterprise Edition 8 provides a robust J2EE platform for the development, deployment, and management of enterprise applications. Key features include transaction management, performance, scalability, security, and integration. The Application Server supports services from Web publishing to enterprise-scale transaction processing.

The Application Server is available in the Platform and Enterprise editions. The Platform edition is free and is intended for software development and department-level production environments. Designed for mission-critical services and large-scale production environments, the Enterprise edition supports horizontal scalability and service continuity via a load balancer and cluster management. The Enterprise edition also supports session continuity via the high availability database (HADB). See the following Application Server Enterprise Edition documentation for more information: http://docs.sun.com/coll/1310.3

BEA WebLogic Server

The BEA WebLogic Server product uses the following definitions:

• Domain. An interrelated set of WebLogic Server resources managed as a unit. A domain includes one or more WebLogic Servers, and might include WebLogic Server clusters.

• Administration Server. A WebLogic Server running the Administration Service. The Administration Service provides the central point of control for configuring and monitoring the entire domain. The Administration Server must be running to perform any management operation on that domain.

• Managed Server. In a domain with multiple WebLogic Servers, only one server is the Administration Server; the other servers are called Managed Servers. Each WebLogic Managed Server obtains its configuration at startup from the Administration Server.

See the following documentation for more information:

http://edocs.beasys.com/wls/docs81/cluster/overview.html#1000572

You start the Administration Server with the following command:

install_dir/config/domain_name/startWeblogic.sh

The local server takes its configuration from the install_dir/config/domain_name/config.xml file.

To start a Managed Server, use the following command:

install_dir/config/domain_name/startManagedWebLogic.sh servername admin_server_url

Instead of taking its configuration from the install_dir/config/domain_name/config.xml local file, the Managed Server takes it from the Administration Server, using HTTP.

The default configuration supported for installing Portal Server on BEA WebLogic Server is a single server that is also the Administration Server for the domain.

A BEA cluster is a set of managed servers in the same domain, that are declared in the WebLogic console as a cluster. When deploying a web application, you use the name of the cluster, not the name of the individual servers. After the deployment, the web application is identically deployed to all machines in the cluster.

Session failover in BEA is described in the following document:

http://edocs.beasys.com/wls/docs81/cluster/failover.html#1022034

Using in-memory replication for HTTP session states requires the following prerequisites:

• Portal Server supports the use of WebLogic Server clusters with in-memory session replication. See the BEA documentation for instructions to set up these clusters. The Sun Java Enterprise System 2005Q5 Installation Guide documents the load balancer configuration for such a cluster using the HttpClusterServlet that ships with BEA. You can also set up other load balancing hardware and software documented by BEA in the same way.

• Session data must be serializable.

• Use the setAttribute to change the session state.

To install a BEA cluster, your BEA license for each machine participating in the cluster must be a special BEA cluster license. See the BEA documentation for the procedure to get the license and set up a BEA cluster with HttpClusterServlet.

IBM WebSphere Application Server

The IBM WebSphere Application Server product uses the following definitions:

• Deployment Manager The deployment manager is the central administrative manager. It does not install the base WebSphere Application Server product on other machines. Only one system hosts the deployment manager.

• Cell A cell is made up of nodes (servers) containing node agents, which are managed by a deployment manager. As the deployment manager federates base WebSphere Application Server nodes, it expands the cell that it manages.

• Clusters A cluster is a group of servers that can be used together for workload balancing by creating additional, nearly identical copies of an application server configuration. This group is the equivalent of BEA's cluster. Clusters are identical multiple Application Server copies. See the IBM WebSphere Application Server documentation for more information: http://www-306.ibm.com/software/webservers/appserv/was/library/library51.html

  WebSphere Application Server Network Deployment edition addresses application servers that run in multiple-server production scenarios. It provides centralized administration, as well as basic clustering and caching support.

WebSphere Advanced Server Network Deployment provides a more robust approach to clustering because it includes a database. In Advanced Server, all servers use the database for the configuration information. You can use the WebSphere administration console, a Swing Java application, or the command-line utilities XMLConfig and wscpthen to manage the servers.