New metric for PVC resize status

[luarx]

Is this a BUG REPORT or FEATURE REQUEST?:
/kind feature

What happened:
In Kubernetes v1.11 the persistent volume expansion feature is being promoted and we can use it to resize PVC. But kube-state-metrics doesn't have a metric to know if a PVC is "resizing"/"already resized but pending of a pod restart"/"resized".

It would be useful to know if a pod must be restarted so that Kubernetes can resize the filesystem of a persistent volume.

What you expected to happen:
Have a metric to know resize state of a PVC and use it to configure alerts of pods that must be restarted to be able to resize the volume.

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version): v1.11.9
• Kube-state-metrics image version

[brancz]

The use case makes perfect sense! How does this show in the PVC object? As that's what we would need to create metrics off of.

[luarx]

Great! I appreciate that :D

In the PVC object there are 3 resizing phases:

1. NORMAL status without asking for a resize or AFTER RESIZING A PVC
   

2. Volume RESIZING
   

3. FILE SYSTEM RESIZE PENDING. In this phase pod must be restarted so that it could be done.
   

So I propose the following metric:

• Name: kube_persistentvolumeclaim_resized_phase
• Phases:
  • Resizing
  • Pending
  • Completed (PVC is not in one of the previous phases)
• Fields (the same as kube_persistentvolumeclaim_status_phase):
  kube_persistentvolumeclaim_resized_phase{endpoint="",instance="",job="",namespace="",persistentvolumeclaim="",phase="",pod="",service=""}
• More fields?
  • LastTransitionTime

What do you think?

[brancz]

I think having condition metric like we do for pods and nodes would be more appropriate here.

[luarx]

Are you talking about kube_node_status_condition? It has 3 status values: true/false/unknow...will we define our 3 phases instead of those so?

[brancz]

It has the condition and status, which seems to be a similar circumstance here. We would have the type and status, which are the required fields for that struct and essentially enums.

[luarx]

Yes, it makes sense! It would work for me :)

[brancz]

You want to give it a go? :)

[zouyee]

It is helpful to troubleshoot the volume condition!

[fejta-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle stale

[luarx]

You want to give it a go? :)

It would be great but I don't have enough time at this time :(

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle rotten

[fejta-bot]

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/close

[k8s-ci-robot]

@fejta-bot: Closing this issue.

In response to this:

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[tariq1890]

/reopen

[k8s-ci-robot]

@tariq1890: Reopened this issue.

In response to this:

/reopen

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[tariq1890]

/help-wanted
/remove-lifecycle rotten
/good-first-issue

[k8s-ci-robot]

@tariq1890:
This request has been marked as suitable for new contributors.

Please ensure the request meets the requirements listed here.

If this request no longer meets these requirements, the label can be removed
by commenting with the /remove-good-first-issue command.

In response to this:

/help-wanted
/remove-lifecycle rotten
/good-first-issue

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[sinhaaks]

Hello, can I work on this issue?

[luarx]

Sure, I think so! 😃

[lilic]

/assign @ankitsinhaiiitg