Why kube-prometheus used metrics.k8s.io instand of custom.metrics.k8s.io?

[terloo]

As I know metrics api group maybe distributed like this

	API Group	application
Resource Metrics	metrics.k8s.io	metrics-server
Custom Metrics	custom.metrics.k8s.io	PrometheusAdaptor
External Metrics	external.metrics.k8s.io	Cloud Provider

After I deploy the mainifest, I found promethes-adaptor used apiGroup metrics.k8s.io in kube-prometheus.But use custom.metrics.k8s.io in his self project.
Why is this?

[metalmatze]

This is probably best asked on https://github.com/kubernetes-sigs/prometheus-adapter directly.

[terloo]

That's why I'm confused.
Prometheus-adapter actually use group custom.metrics.k8s.io in custom-metrics-apiservice.yaml