Create a rules file - Amazon Managed Service for Prometheus

Create a rules file

To use rules in Amazon Managed Service for Prometheus, you create a rules file that defines the rules. An Amazon Managed Service for Prometheus rules file is a YAML text file that has the same format as a rules file in standalone Prometheus. For more information, see Defining Recording rules and Alerting rules in the Prometheus documentation.

The following is a basic example of a rules file:

groups:
  - name: cpu_metrics
    rules:
      - record: avg_cpu_usage
        expr: avg(rate(node_cpu_seconds_total[5m])) by (instance)
      - alert: HighAverageCPU
        expr: avg_cpu_usage > 0.8
        for: 10m
        keep_firing_for: 20m
        labels:
          severity: critical
        annotations:
          summary: "Average CPU usage across cluster is too high"

This simple example creates a new metric using a recording rule, called avg_cpu_usage and then uses that in an alert. The following describes some of the properties used. For more information about alerting rules and other properties you can include, see Alerting rules in the Prometheus documentation.

  • record: avg_cpu_usage – This recording rule creates a new metric called avg_cpu_usage.

  • expr: avg(rate(node_cpu_seconds_total[5m])) by (instance) – This expression for the recording rule calculates the average rate of CPU usage over the last 5 minutes for each node, grouping by the instance label.

  • alert: HighAverageCPU – This alert rule creates a new alert called HighAverageCPU

  • expr: avg_cpu_usage > 0.8 – This expression tells the alert to look for samples where the average CPU usage goes over 80%.

  • for: 10m – The alert will fire when the expression is met for 10 minutes. In this case, the samples are an average over 5 minutes, so the alert will fire when it receives at least 2 samples that are over the threshold.

  • keep_firing_for: 20m – This alert will continue to fire until the samples are below the threshold for at least 20 minutes. This can be useful to avoid the alert going up and down repeatedly in succession.

For more alerting rule examples, see Alerting rule examples.

Note

You can create a rules definition file locally and then upload it to Amazon Managed Service for Prometheus, or you can create, edit and upload the definition directly within the Amazon Managed Service for Prometheus console. Either way, the same formatting rules apply. To learn more about uploading and editing your file, see Upload a rules configuration file to Amazon Managed Service for Prometheus.