4. Plugins

Plugins are divided into a few concepts: commands, fields, and named command instances:

• Commands are executed once per instance (see below) per machine, and collect a number of fields.
• Fields are the individual pieces of data collected when running each command.
• Named command instances allow the same command to be run more than once on a single machine. By default, a command is run once, and the fields are collected for the default instance. If, for instance, a machine has two MySQL daemons running, using named command instances, emt can gather the same set of stats for each instance and track them separately. For more information on instances see the configuration section.