The Common Monitoring Model (CMM)

The basis of a standardized monitoring mechanism is the definition of what objects are monitored and the adoption of these objects across all monitored components. To this end, the monitoring architecture defines the Common Monitoring Model (CMM) as an extension of the Common Information Model (CIM) maintained by the Distributed Management Task Force (DMTF). CMM is both an information model specifying monitored objects such as computer, application, and so on, and a data model specifying uniform values such as the operational status values. As part of the information model, CMM also defines the attributes of an object, for example the number of requests handled by a service, and relations between objects, such as the fact that a service is hosted on a certain computer.

Thanks to CMM, concepts such as applications, services, points of access, and so on are the same for all product components, even if the underlying implementation is different. For example, Web Server might expose a service that handles HTTP requests while Directory Server might expose a service that handles LDAP requests. However the standard object will capture what is common to these two functions, for example the ability to measure the number of requests handled, the average time to respond to a request over a given time period, and so on.

Furthermore, certain data values are standardized so that their meaning is uniform across the entire system. For example, the operational status DEGRADED always means that a service is still available but performance has dropped significantly, no matter which product component is being monitored.

The CMM specification is embodied in the Java interfaces and classes used for the instrumentation, which are described in Appendix A, CMM Object Reference.