migrate kubelet custom metrics to stability framework part 1

[RainbowMango]

What type of PR is this?
/kind feature

What this PR does / why we need it:
Currently, custom metrics emitted from kubelet do not offer any stability guarantees.

And #83062 tries to make it possible to do so.

About metrics stability please refer to KEP .

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:
There are still some custom metrics under pkg/kubelet/server that I'd prefer to do it later.
Because it's a little different(can't make it one-line migration) and I'm trying to find a way to deal with them.

Does this PR introduce a user-facing change?:

Following metrics from kubelet are now marked as with the ALPHA stability level:
kubelet_container_log_filesystem_used_bytes
kubelet_volume_stats_capacity_bytes
kubelet_volume_stats_available_bytes
kubelet_volume_stats_used_bytes
kubelet_volume_stats_inodes
kubelet_volume_stats_inodes_free
kubelet_volume_stats_inodes_used
plugin_manager_total_plugins
volume_manager_total_volumes

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

- [KEP]: https://github.com/kubernetes/enhancements/blob/master/keps/sig-instrumentation/20190404-kubernetes-control-plane-metrics-stability.md

/priority important-soon
/milestone v1.17

[RainbowMango]

Unit test failed as we need another functionality, the one like CollectAndCompare but especially for custom collector.

/hold
for a while and get back soon.

[edit] This rely on some functionalities for custom collector testing and they are in #84919

[mattjmcnaughton]

Adding @dashpole for the initial review, as he is in the intersection of those who participate in sig-node and those who participated in the linked KEP.

cc @dashpole

Removing myself as I don't have much, if any, context on the overall effort.

/uncc

[dashpole]

/assign

[RainbowMango]

/test pull-kubernetes-e2e-gce-storage-slow
/hold cancel

/assign @saad-ali
for pluginmanager and voluemanager

[dashpole]

Great work!
/lgtm
/approve

[RainbowMango]

/assign @saad-ali

@kubernetes/sig-node-pr-reviews

[josiahbjorgaard]

@RainbowMango The v1.17 code freeze is coming up on 11/14 at 5PM pacific time. This PR will need to be merged before then for v1.17.

[derekwaynecarr]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dashpole, derekwaynecarr, RainbowMango

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• pkg/kubelet/metrics/OWNERS [dashpole,derekwaynecarr]
• pkg/kubelet/pluginmanager/OWNERS [derekwaynecarr]
• pkg/kubelet/volumemanager/OWNERS [derekwaynecarr]

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[rajivmucheli]

Hi @RainbowMango , would these metrics be visible only in v1.17 ? not before or after ? I dont see ONLY these volume metrics in kubelet scrape on v1.15.

I had to ask here since i had no response to #89733

[RainbowMango]

@rajivmucheli

would these metrics be visible only in v1.17 ?

No, this PR didn't change the visibility of metrics.

[rajivmucheli]

Oh ok, only these metrics fail to be visible on k8s v1.15, could you please assist on how to troubleshoot this issue on this PR or my PR? Are there any other metrics to determine pv consumption?