Migrate from Endpoint to EndpointSlices

[slashpai]

What is missing?
Endpoints are deprecated in k8s 1.33, to avoid warnings and stay upto-date with upstream k8s we need to move to EndpointSlices.

It involves at least

• Define serviceDiscoveryRole: EndpointSlice for the Prometheus custom resource.
• Update RBAC to grant permissions on endpointslice resoures instead of endpoints.

Why do we need it?
https://kubernetes.io/blog/2025/04/23/kubernetes-v1-33-release/#deprecation-of-the-stable-endpoints-api

Environment

• kube-prometheus version:

  Insert Git SHA here

Anything else we need to know?: