Prometheus Metrics: How To Change The Metric Name?

Find a way to re-define and re-organize the name of your Prometheus metrics to meet your requirements

Prometheus Metrics: How to change the names of a metric? — Photo by Chris Ried on Unsplash

Prometheus has become the new standard when we’re talking about monitoring our new modern application architecture, and we need to make sure we know all about its options to make sure we can get the best out of it. I’ve been using it for some time until I realized about a feature that I was desperate to know how to do, but I couldn’t find anywhere clearly define. So as I didn’t found it easily, I thought about writing a small article to show you how to do it without needed to spend the same time as I did.

We have plenty of information about how to configure Prometheus and use some of the usual configuration plugins, as we can see on its official webpage [1]. Even I already write about some configuration and using it for several purposes, as you can see also in other posts [2][3][4].

One of these configuration plugins is about relabeling, and this is a great thing. We have that each of the exporters can have its labels and meaning for those, and when you try to manage different technologies or components makes complex that all of them match together even if all of them follow the naming convention that Prometheus has [5].

But I had this situation, and I’m sure you have gone or will go towards that as well, that I have similar metrics for different technologies that for me are the same, and I need to keep them with the same name, but as they belong to other technologies they are not. So I need to find a way to rename the metric, and the great thing is that you can do that.

To do that, you just need to do a metric_relabel configuration. This configuration applies to relabel (as the name already indicates) labels of your prometheus metrics in this case before being ingested but also allow us to use some notable terms to do different things, and one of these notable terms is __name__. __name__ is a particular label that will enable you to rename your prometheus metrics before being ingested in the Prometheus Timeseries Database. And after that point, this will be as it will have that name since the beginning.

How to use that is relatively easy, is as any other relabel process, and I’d like to show you a sample about how to do it.

- source_labels: [__name__]

regex:  'jvm_threads_current'

target_label: __name__

replacement: 'process_thread_count'

Here it is a simple sample to show how we can rename a metric name jvm_threads_current to count the threads inside the JVM machine to do it more generic to be able to include the threads for the process in a process_thread_count prometheus metrics that we can use now as it was the original name.