Technical data

1 Overview of WebLogic System Administration
1-4 Configuring and Managing WebLogic Server
Figure 1-1 depicts a possible configuration of a WebLogic Server Domain—one of
many possible configurations.
In the depicted domain, there are three physical machines.
Machine A is dedicated as the Administration Server and hosts one instance of
WebLogic Server. The System Administration Tools communicate with the
Administration Server to perform configuration and monitoring of the servers and
applications in the domain. The Administration Server communicates with each of the
Managed Servers on behalf of the System Administration Tools. The configuration for
all the servers in the domain is stored in the configuration repository, the
config.xml
file, which resides on the machine hosting the Administration Server.
Machines B and C each host two instances of WebLogic Server, WebLogic Servers 1
through 4. These instances are called Managed Servers. The Administration Server
communicates with an instance of Node Manager running on each machine to control
startup and shutdown of the Managed Servers.
WebLogic Servers 2 and 4 are part of a WebLogic Cluster(outlined in red). This cluster
is running an application that responds to HTTP requests routed to the cluster from a
hardware load balancer. (You could also use an instance of WebLogic Server to
provide load balancing.) The load balancer processes HTTP requests from the Internet
after they have passed through a firewall. The load balancer and firewall are not part
of the domain. A replicated copy of objects such as HTTP sessions is passed between
the two cluster members to provide failover capability.
WebLogic Server 1 runs an application that uses Java Database Connectivity (JDBC)
to access a database server running on another physical machine that is not part of the
WebLogic Domain.
Note: The pictured domain is only intended to illustrate the concepts of a WebLogic
Server domain and how you manage the domain. Many possible
configurations of servers, clusters, and applications are possible in a
WebLogic Server domain.