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serviceprometheusmetricspromql

Get percentage rate between two metrics in a define interval [Prometheus]

I have a question about Prometheus. In my service I have 2 Counters, metric_1 is the total number of requests and metric_2 is the number of failed requests. I need to derive a further metric from these to determine the error rate of requests in terms of percentage in a defined interval (e.g. 2 hours). How can I achieve this through, for example, PromQL?

Solution

  • Try something like the following:

    increase(metric_2[2h]) / increase(metric_1[2h])

    See increase() function documention.

    It is assumed that metric_1 and metric_2 are counters. If these metrics are gauges, then increase() must be substituted by sum_over_time().