Alert rules¶
Alerts are defined by a sequence of queries and math expressions that are executed periodically. When the last query/expression returns a non-zero value, the alert is triggered and the notification actions are performed.
Usually, an alert rule consists of:
Query to retrieve the data points,
Reduce the query into single value
Check the single value against a threshold
Optional additional information attached to the alert
The following clip defines an alert triggered when the battery voltage is below 2 V. The alert will be triggered for any device because we didn’t restrict the query to a certain device (node). However, we need to group the data into individual devices; otherwise, only one alert will be triggered for all devices.
Contact points¶
Contact points define the destinations to which the alerts are sent. You can configure various types contact points according to your needs. Common contact point types are email, slack, webhook, telegram, etc.
The following clip shows creating an email contact point.
Notification policies¶
Once you have alerts and contact points, you can configure notification policies to define which alerts are sent to which contact points.
In the following clip, the alert is matched via its name, and its contact point is set to the test email. As shown here, if you disable the grouping, you will receive a separate notification for each device. Otherwise, you will receive a single notification combining all triggered alerts within the group.