Area(s)

area:k8s

Is your change request related to a problem? Please describe.

Part of #1032.

This issue is for adding the statefulset related metrics.

Describe the solution you'd like

The following metrics are already implemented by the Collector:
k8s.statefulset.desired_pods
k8s.statefulset.ready_pods
k8s.statefulset.current_pods
k8s.statefulset.updated_pods

ref: https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/v0.114.0/receiver/k8sclusterreceiver/documentation.md#k8sstatefulsetcurrent_pods

Describe alternatives you've considered

No response

Additional context

API ref: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.30/#statefulsetstatus-v1-apps

I would like to validate the names here though and make sure that we are happy with the .ready_pods and .desired_pods. The alternative would be to have them as .desired and .available as we have in the deployment and replicaset metrics (#1636)?

@TylerHelmuth @povilasv @dmitryax could you verify if that's the desired modeling here for any specific reason or if it would make sense to change it so as to be consistent with the other mentioned namespaces?