Notebook culling metrics are not displayed

[AnubisFUp]

Checks

• I have searched the existing issues.
• My issue is related to one of the components in the kubeflow/notebooks repository.

Kubeflow Notebooks Version

v1

Kubeflow Platform

kustomize

Kubernetes Distribution

selfhosted

Kubernetes Version

Client Version: v1.34.1
Server Version: v1.29.13

Description

Hi!
I assumed that the metrics notebook_culling_total and last_notebook_culling_timestamp_seconds would be exported in the /metrics section, but they are not there.
Is this possible because they are not called in this part?

notebooks/components/notebook-controller/pkg/metrics/metrics.go

Lines 74 to 79 in 669de15

	func (m *Metrics) Collect(ch chan<- prometheus.Metric) {
	m.scrape()
	m.runningNotebooks.Collect(ch)
	m.NotebookCreation.Collect(ch)
	m.NotebookFailCreation.Collect(ch)
	}

Relevant Logs

[aniketpati1121]

These metrics are defined but not exposed via the Collect() method.
They need to be added to Collect() so Prometheus can scrape them

[amazephoenix-bit]

Thanks for the analysis!
I can work on exposing the missing notebook culling metrics via the Collect() method and open a small PR.