This chapter was packed with concepts concerning reacting to events that happen in your monitored environment. We learned how to describe conditions that should be reacted to as trigger expressions. Triggers themselves have useful functionality with dependencies, and we can make them depend on each other. We also explored several ways of reducing trigger flapping right in the trigger expression, including using functions such as min(), max(), and avg(), as well as trigger hysteresis.
Among other trigger tricks, we looked at the following:
- Using the nodata() function to detect missing data
- Using the same nodata() function to make a trigger time out
- Creating triggers that have different used disk space threshold values based on the total disk space
- Creating triggers that only work during a specific time period
- Having a relative threshold, where recent data is compared...