Monitoring Ranges

Monitoring Ranges

Overview

If a monitor supports alerting when a given value is above or below a given threshold, it is possible to be notified if a given value is inside or outside of a range.

Examples

Metric

Metric a reports discrete values from 0 to 10 representing a status and you want to be notified if the metric is not between 4 and 8. Mathematically, the difference between the metric and the center of the range (6) should never be more than 2.

8 > a > 4 <=> abs(6-a) < 2 <=> abs(6-a) - 2 < 0
  • To be notified if the value is outside the range, the monitor condition should be abs(6-a) - 2 > 0.
  • To be notified if the value is inside the range, the monitor condition should be 2 - abs(6-a) > 0.

Theoretical

A range is defined by x > a > y with a being the metric in question.

  • To be notified if the value is inside the range, the monitor condition should be: abs((x-y/2) - a) - (x-y)/2 > 0.
  • To be notified if the value is outside the range, the monitor condition should be: (x-y)/2 - abs((x-y/2) - a) > 0.

Troubleshooting

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