AggreGate has an extensive support for alerting, which is one of the essential tools in modern monitoring systems. Alerts notify system operators when something goes wrong in any part of a distributed system. Without alerts, an operator would have to constantly go around the system and click devices just “to make sure everything is OK”. Alerts make sure operators notice what they should notice.
Every user has their own set of alerts. Alerts can also be shared. An alert compises:
- Triggers
- Notification Rules
- Corrective Actions
Alert Triggers
Every alert has one or more triggers defining when to raise it. These can be either event triggers or state triggers.
An
event trigger is raised when an event of a certain type conforms to the trigger condition. This condition is flexibly configured by an expression, allowing complex checkings. For example, a vehicle monitoring system may generate an alert if an
impact event received from a vehicle controller indicates that
impact strength exceeds a threshold.
State trigger can either be raised in response to a certain state, or to any change in the state of whatever is being monitored. State trigger periodically check a device or system property (also pointed by a custom expression). They have a configurable hysteresis time, for activating the alert only if the condition lasts longer than a certain time. For example, a state trigger may raise an alert if
the temperature rises over 120 degrees for more than 3 minutes.
Every trigger may check one or more devices or resources. Combined with the ability to set up multiple triggers per alert, this allows for very flexible alerts.
Notification Rules
Alert notifications inform humans about alert conditions and provide related information. Notifications can be in the form of:
- Popup messages to the operator. (May also prompt for acknowledgement)
- Custom sound.
- E-mail notifications (also to multiple recipients). Alerts may be acknowledged by replying to e-mail notifications.
- SMS notifications.
In plus, alert's
corrective actions may implement any other notification schemes.
Features 