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.