feat: Add CSI volume attributes to PV info metric

[machadovilaca]

What this PR does / why we need it:

This PR adds a new csi_mounter and csi_map_options for CSI PV in kube_persistentvolume_info metric, to track the mounter used by the volume, and the respective map options configured

How does this change affect the cardinality of KSM: (increases, decreases or does not change cardinality)

• adds 2 new labels for kube_persistentvolume_info
• but these label values should be static for most of the lifetime of a volume, therefore, since we already have the volume name in the metric, metric total cardinality is not expected to increase

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

[openshift-ci]

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[simonpasquier]

👋 any reason why it can't be submitted upstream first? In general, we don't carry downstream patches.
cc @rexagod

[openshift-ci]

@machadovilaca: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-agnostic-cmo	56eebc1	link	true	/test e2e-agnostic-cmo

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[machadovilaca]

@simonpasquier I opened kubernetes#2133, but the opinion was that these are very CSI drivers specific and would be hard to add them there

[rexagod]

Hey @machadovilaca, we don't really merge any "out-of-tree" changes downstream, since that would diverge and open us on unpredictable front given how the areas affecting such a patch will change upstream from one release to another. IMO getting this in upstream would be the way to go, using --metric-opt-in-list as you've commented.

[simonpasquier]

IIUC --opt-in-metrics-list is different because the goal is to enable optional metrics while the change is about adding/enabling new labels to an already existing metric.

[rexagod]

ACK, I was under the impression that since adding these labels to the existing metric is getting some pushback, we could possibly introduce a new metric that folks can opt-in to. However, I see that this could open us (upstream) up for merging one-off metrics for similar use-cases, and thus will need to be evaluated on a case-by-case basis giving priority to the fact that even the hidden metrics are widely beneficial, if not as much as the ones enabled by default. An --opt-in-labels-list flag might be an alternative worth exploring as well.

[machadovilaca]

submitted a new opt-in metric
kubernetes#2133