Exclude namespaces from service discovery

[omerlh]

Proposal

Use case. Why is this important?
I want to apply sample_limit to protect Prometheus from a service that exposes too many metrics. The challenge is applying the limit only on applicative namespaces - I want to exclude kube-system from the limit or apply a different limit to this namespace. To achieve that, I would like to define 2 service discovery jobs:

• One that use __meta_kubernetes_namespace to scrape only kube-system.
• One that scrapes all namespaces besides kube-system.

I can achieve that by using __meta_kubernetes_namespace to specify all the namespaces that exist today. This solution will work, but is cumbersome and require changes each time a namespace is added. I would like to have a more dynamic solution.

[brian-brazil]

It makes more sense to ask questions like this on the prometheus-users mailing list rather than in a GitHub issue. On the mailing list, more people are available to potentially respond to your question, and the whole community can benefit from the answers provided.

[omerlh]

I asked first on the slack channel - you can see my message here. I assumed the mailing list is similar to the mailing list.