The growth of large-scale distributed applications in the past decade has been impressive. Mission-critical business applications have evolved from a sequence of programs running on a single computer to business components running on different machines scattered throughout a network. Managing one application running on a single computer is fairly straightforward; you can monitor the health of the application through the use of a single log file, or operator console, and tools provided by the operating system. The difficulty of managing today’s distributed systems has increased along with the complexity of those systems. When considering a management solution for today’s enterprise applications, some questions arise:
Which management solution is best for the application?
What standards should a management solution follow?
How much effort is required to enable the components of the application to be managed?
Java Management Extensions ( JMX), the result of the Java Community Process ( JCP) Java Specification Request ( JSR) 3, was designed to deal with all of these questions. JMX was designed to address the management needs of applications written for the Java platform and to be compatible with existing management standards, such as the Simple Network Management Protocol (SNMP), which is the standard for management of enterprise networks. It was also designed so that instrumentation of resources to put them under the control of a management application is as easy as possible.
A resource is any entity in the system that needs to be monitored and/or controlled by a management application; resources that can be monitored and controlled are called manageable. A management application is a piece of software that can be used to monitor and control manageable resources (typically remotely). Managing a system of manageable resources is what we call system management. The JMX architecture enables Java applications (or systems) to become manageable.
Three fundamental questions must be addressed by any complete management solution:
How do I make my resources manageable?
Once my resources are manageable, how do I make them available (visible) for management?
Once my resources are visible for management, how do management applications access them?
The JMX architecture is composed of three levels, each of which answers one of these questions.