Application management
J2EE applications and modules include an XML-based deployment descriptor that specifies various J2EE artifacts that pertain to applications or modules. The J2EE artifacts include...
- EJB definitions
- security role definitions
- EJB references
- resource references
These artifacts define various unresolved references that the application logic uses. The J2EE specification requires that these artifacts map to J2EE platform-specific information, such as that found in WAS (WAS), during deployment of J2EE applications.
The application assembly tools that WAS supports, as well as the application management support that is provided with the product, facilitate collection of certain WAS information. The collected information is used to resolve references that are defined in various deployment descriptors in a J2EE application. This information is stored in the application EAR file in conjunction with the deployment descriptors.
The following diagram shows the structure of an EAR file that is populated with deployment information that is specific to WAS.
The application management architecture provides a set of classes with which deployers can collect WAS deployment information. This information is also referred to as binding information, and is stored in the application EAR file.
The deployer can install the EAR file into a WAS configuration by using the AppManagement interface.
The application management support in WAS provides functions such as installing and uninstalling applications, editing binding information for installed applications, updating the entire application or part of the application, exporting the application, and so on. The interface...
com.ibm.websphere.management.application.AppManagement
...which is exposed as a JMX-based AppManagement MBean in WAS, provides this functionality. Code that runs on the server or in a stand-alone administrative client program can access the interface. Access to the application management functions is also possible in the absence of WAS. This mode, known as local mode, is particularly useful for installing J2EE applications as part of product installation. For WAS ND, the AppManagement MBean is present in the deployment manager only, which facilitates centralized configuration and administration.
Application deployment in a ND configuration
The following diagram explains application deployment for the ND product:- The application EAR file that you install is stored in the master configuration repository of the deployment manager, with the application metadata.
- The configuration synchronization operation replicates the application in the master repository into the repository of the target node.
- The application EAR file is extracted to the installation destination of the target node at the end of the synchronization operation.
- The WAS run time reads the application business logic such as EJB classes, servlets, and JavaServer Pages from the installation destination while serving application client requests.
- WAS reads the application metadata, such as deployment descriptors and WAS bindings during application startup from the configuration repository or the installation destination only, depending on the option that is specified during application installation.
