Monitoring with Ganglia

Appendix A. Advanced Metric Configuration and Debugging

Module Metric Definitions

The following tables describe the metric modules that are part of the distribution of the Ganglia monitoring system. In addition to these metric modules, there are also a number of other modules that are available through the Ganglia module git repository. As new modules are developed, many developers share them with the Ganglia community through the Ganglia module repository. The Ganglia module git repository is open to the public, and the modules are free to download and use. Some of the additional modules that are available from this repository include modules for monitoring an Apache Web Server, MySQL database, and Xen virtual machine, as well as Tomcat and Jetty servlet monitoring through JMX.

Mod_MultiCPU

Prior to the introduction of Mod_MultiCPU, gmond was able to produce only a single CPU-related value for each of the various CPU metrics that it reported. If the hardware architecture supported multiple CPUs, gmond reported only the overall usage rather than the usage for each individual CPU. The Mod_MultiCPU module is capable of detecting how many CPUs exist on the system and constructs the series of metric definitions for each one (Table A-1). Through the configuration of Mod_MultiCPU, all CPU-related metrics can be reported for each CPU detected on the system.

Table A-1. Mod_MultiCPU: monitor individual CPU metrics

Metric Name	Description
multicpu_user	Percentage of CPU utilization that occurred ...