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Java Management Extensions

Extensive knowledge of JMX is not required to administer WAS. Familiarity with some basic concepts, such as MBeans, can be useful when you are writing scripts for wsadmin.

Provides a standard way of exposing Java resources. The system management functionality of WAS is based on the use of JMX. All operations on managed resources go through JMX functions.

The following WAS administration tools use JMX:

• WebSphere dmgr console
• wsadmin scripting client
• Administration client Java API

JMX architecture

Instrumentation layer	Dictates how resources can be wrapped within special Java beans called managed beans (MBeans).
Agent layer	Consists of the MBean server and agents, which provide a management infrastructure. The services implemented include monitoring, event notification, and timers.
Management layer	Defines how external management applications can interact with the underlying layers in terms of protocols, APIs, and so on.

The use of JMX opens the door for third parties to provide management tools to administer WAS, for example:

• Programs written to control the WAS runtime and its resources by programmatically accessing the JMX API

• Applications that include custom JMX MBeans as part of their deployed code, allowing their components and resources to be managed through the JMX API

See:

• JMS Management
• JMS Programming

JMX MBeans

Resources are managed by JMX MBeans, which wrap runtime resources. For example, to expose an application server as a manageable resource, WAS provides an application server MBean.

External applications can interact with the MBeans through JMX connectors and protocol adapters. Connectors are used to connect an agent with a remote JMX-enabled management application.

Each JMX-enabled JVM contains an MBean server that registers all of the MBeans in the system. It is the MBean server that provides access to all of its registered MBeans. There is only one MBean server per JVM.

WAS provides a number of MBeans, each of which can have different functions and operations available, for example:

• An application server MBean can expose operations, such as start and stop.
• An application MBean can expose operations, such as install and uninstall.