Resource management and JMX - JMX in Action - page 14

1.3 T he JMX architecture

The JMX architecture is a component architecture designed to build flexibility
and usefulness into a management environment. It does so by providing a mech-
anism for agents (and ultimately MBeans) to be reached by many different pro-
tocols and by many different mechanisms. This section breaks the architecture
into its three main layers—instrumentation, agent, and distributed—and dis-
cusses each by following a simple use case as it applies to each layer. Table 1.1
lists the three layers with brief descriptions.

Table 1.1 The three JMX architectural layers

Layer Description

Distributed layer Contains components that enable management applications

to communicate with JMX agents

Agent layer Consists of agents and their MBean servers

Instrumentation layer Contains MBeans representing their manageable resources

Each layer contains some of the various components we have already discussed,
but you need to understand how everything works together.

1.3.1 Example: managing the bicycle shop server

In order to help you better understand the purpose of each layer, and to tie
them together at the same time, we will walk through a simple use case. Let's say
the bicycle shop web site has a server application that manages inventory and
suppliers. This application is used to keep track of sales, inventory, and orders to
suppliers on a scheduled basis. Suppose this application can be configured to use
different order formats, logging levels, and schedules. Because this application is
critical to the business, it needs to be configurable (or manageable) without caus-
ing a shutdown of operations.
In many situations like this, you would expect the application to have a con-
sole to which you could connect in order to change the logging level, validation
process, or storage location. However, a business may have many such applica-
tions, each with its own configuration or management tools; in this case, you
would have to go to each application and use the individual tool to change the
logging level. Managing such an environment as a unit would be very difficult.
Figure 1.1 shows this type of situation.
In contrast, let's consider this situation from a JMX point of view. How can
JMX make this heterogeneous management environment work better? You can