InfoCenter Home > 6a: Administrative overview of Version 3.5
Looking for a summary of the tasks and resources you can manage with IBM WebSphere Application Server Version 3.5? See the quick reference, including links to instructions and descriptions of resource settings. Administrative modelIBM WebSphere Application Server provides administrators with a single system view of applications that are typically deployed across multiple machines. An administrator working on a physical machine can remotely administer resources located on another physical machine. These elements comprise the WebSphere administrative model:
Details about the adminstrative databaseEach resource in the WebSphere administrative domain corresponds to an object in the administrative database. For example, when the administrator configures a new application, a corresponding application object is created in the administrative database. In this way, the administrative database contents mirror the contents of the administrative domain. The administrative database contains descriptive information about the resources that are configured to run on each node in the domain. For example, the administrative database contains the names of application servers, the node each server is running on, the enterprise beans installed in each server, and the current state of each server (for example, running). The administrative database allows the administrator to manage the domain from any machine, because
all information is stored in a central location. Each administrative server has a central view of
resource configuration information about in the domain. When the administrator modifies a resource
configuration, the changes are seen by all administrative servers. The resources in a WebSphere administrative domain are represented in the administrative database as entity beans with container-managed persistence (CMP). The persistent data associated with a resource (for example, the name, current state, and working directory of an application server) is stored in the administrative database. Administration occurs through method calls to resource beans in the administrative server. Administrative clients make requests on the administrators' behalf to an administrative server to access or modify a resource in the domain. An administrative server also communicates with other, remote administrative servers to delegate tasks and to respond to requests. In the administrative server, session beans invoke methods on the resource beans. For example, the administrator can start, stop, ping, and modify application servers in the administrative client, which in turn invokes methods on the resource beans for the application servers. Relationships among resources (the topology tree)The Topology tree demonstrates the relationships among resources. The relationship is the "containment hierarchy." The Topology tree is visible in the Java console (WebSphere Administrative Console). The containment hierarchy imposes a structure on the topology of the administrative domain. Becoming familiar with the hierarchy will make administrative tasks seem easier to accomplish. Anyone who has worked with directory and file representation systems, such as Microsoft Windows Explorer, has already been introduced to the concept of containment. Containment defines a relationship in which one resource is a part or "child" of another resource. If you have ever tried creating a directory in a file, you know that your file management program will not allow it. The directory-file containment hierarchy imposes the following rule: Directories can contain files, but files cannot contain directories. Similar relationships and rules exist among resources in the WebSphere Application Server administrative domain. For example, an application server resource can contain just one servlet engine. Some relationships depend on each other. Adding a servlet to the administrative domain requires a Web application. A servlet engine must exist to contain the Web application. Finally, an application server must exist to support the Web application containing the servlet. The containment hierarchy enables:
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