Metric data are collected according to a schedule. However, some actions occur on a resource sporadically, such as sudden system shutdowns. These are events. Since event data can be generated randomly, events are sent to agents immediately when they are detected.
20.1. Events, Logs, and Resources
Operating and some server types keep their own log files and register a steady stream of information about incidents for that resource, from simple debug information to critical errors. Metrics are collected on a (more or less) set schedule. Events are entirely random, because they are based on real actions as they occur. Events, then, give a different perspective on resource performance.
Events monitoring tracks those streaming log file messages. In a sense, JBoss ON event monitoring is a filtered log viewer. When events are enabled, all of the log messages flow through JBoss ON's event viewer. However, the types of messages that JBoss ON records and displays can be limited in the event configuration so that only certain types of messages or messages matching certain strings are included in the events view.
A handful of resource types record and display events:
Windows (Windows event logs)
Apache server (log files)
JBoss EAP server (log files)
Events must be enabled and configured for a resource before they become active.
Default events are taken from standard log files. Custom resource types can identify event sources in logs or in asynchronous messaging systems such as a JMX notification or a JMS messaging system.