Prometheus Query to Count Unique Label Values

To count unique label values in Prometheus, you can use the count function along with the by clause to aggregate metrics based on a specific label. This is useful when you want to find out how many unique values a particular label has within a given metric.

Example Scenario

Let’s say you have a metric called http_requests_total that includes a label named instance. You want to count how many unique instances are being tracked.

PromQL Query

Here’s how you can construct your query:

count(http_requests_total) by (instance)

Breakdown of the Query

• count(http_requests_total): This part of the query counts the number of occurrences of the http_requests_total metric across all instances.
• by (instance): This clause specifies that the counting should be grouped by the instance label. As a result, you will get a count of http_requests_total for each unique instance.

Getting Distinct Unique Values

If you want to get the distinct unique values of a label (rather than just counting how many times each unique value appears), you can use the count function on the label_replace function. Here’s an example:

count(count(http_requests_total) by (instance))

Additional Example: Counting Unique Values of a Different Label

Suppose you want to count unique values of another label, such as status, from the same metric:

count(http_requests_total) by (status)

This will give you the count of requests grouped by the status code.

Got an article suggestion? Let us know

Explore more

Prometheus

What Is A Bucket In Prometheus?

Questions

Limitations of Prometheus Labels

Questions

How To Manage Prometheus Counters

Questions

What Is The Job Label In Prometheus?

Questions

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.