How to rename label within a metric in Prometheus

Question

I have a query:

node_systemd_unit_state{instance=\"server-01\",job=\"node-exporters\",name=\"kubelet.service\",state=\"active\"} 1

I want the l

Answer 1

I got tired of all the fragmented documentation and I feel I provided a better answer in this post here: https://medium.com/@texasdave2/replace-and-remove-a-label-in-a-prometheus-query-9500faa302f0

Replace is not a true REPLACE

Your goal is to simply replace the old label name “old_job_id” with a new label name “new_task_id”. Prometheus label_replace will really “add” the new label name. It will preserve the old label name as well… So, that could be a problem, it’s not a true “replace in place”.

So if you want to “add” your new label name and “remove” the old label name, you need to do this:

sum without (old_job_id) (label_replace(metric, "new_task_id", "$1", "old_job_id", "(.*)"))

Here’s how this reads:

• sum without (old_job_id) will remove the old label name from the query output

• metric is your metric, like “node_filesystem_avail_bytes”

• “new_task_id” is where you would put your new label name

• “$1” is regex for using the string in new label name, don’t change this

• “old_job_id” is where you’ll put your old label, the one you want to get rid of (.*……. that mess is regex that will replace the whole label name