generic ephemeral inline volumes

[pohly]

Enhancement Description

• One-line enhancement description (can be used as a release note): inline volumes with normal provisioning
• Kubernetes Enhancement Proposal: generic ephemeral inline volumes KEP #1701
• Primary contact (assignee): @pohly
• Responsible SIGs: @kubernetes/sig-storage-feature-requests
• Enhancement target (which target equals to which milestone):
  • Alpha release target: 1.19
  • Beta release target: 1.21
  • Stable release target: 1.23

The current CSI ephemeral inline volume support is designed for CSI drivers that are specifically written for such volumes. The assumption is that such volumes can be created and destroyed quickly on a node together with the pod. Parameters are driver specific.

But ephemeral inline volumes are also useful in combination with traditional storage drivers, for example as temporary scratch space. The goal is to enable ephemeral inline volumes such that:

• normal storage drivers can provide them without having to be modified for that
• all of the usual volume parameters (size, storage class) are available
• storage capacity tracking and pod scheduling works for them

[harshanarayana]

Hey there @pohly -- 1.19 Enhancements shadow here. I wanted to check in and see if you think this Enhancement will be graduating in 1.19?

In order to have this part of the release:

1. The KEP PR must be merged in an implementable state
2. The KEP must have test plans
3. The KEP must have graduation criteria.

The current release schedule is:

• Monday, April 13: Week 1 - Release cycle begins
• Tuesday, May 19: Week 6 - Enhancements Freeze
• Thursday, June 25: Week 11 - Code Freeze
• Thursday, July 9: Week 14 - Docs must be completed and reviewed
• Tuesday, August 4: Week 17 - Kubernetes v1.19.0 released

If you do, I'll add it to the 1.19 tracking sheet (http://bit.ly/k8s-1-19-enhancements). Once coding begins please list all relevant k/k PRs in this issue so they can be tracked properly. 👍

Thanks!

[harshanarayana]

Hey @pohly, I'm following up on my previous update on this Enhancement being part of the v1.19 release.

Do you happen to have any update on the possiblity of this being included in the release v1.19?

Thanks again for your time and contributions. 🖖

[harshanarayana]

Hey @pohly, I'm following up on my previous update on this Enhancement being part of the v1.19 release.

Do you happen to have any update on the possiblity of this being included in the release v1.19?

Thanks again for your time and contributions. 🖖

[pohly]

@harshanarayana: please track this as a new alpha feature for 1.19.

The KEP still needs to be merged, but we already discussed it and should get there soon.

[harshanarayana]

Hey @pohly, thank you for confirming the inclusion into v1.19.. I will update the tracking sheets accordingly.

/milestone v1.19
/stage alpha

[harshanarayana]

Hey @pohly, Enhancement shadow for the v1.19 release cycle here. Just following up on my earlier update to inform you of the
upcoming Enhancement Freeze scheduled on Tuesday, May 19.

I noticed that the KEP is still in flight. As per the requirements, the KEP should be merged and implementable for it to be considered for the release v1.19.

Please feel free to reach out in case if you need any more information.

Regards, Harsha

[zestrells]

Hi @pohly - My name is Zachary, 1.19 Docs shadow. Is this enhancement work planned for 1.19 and does it require any new docs (or modifications to existing docs)? If not, can you please update the 1.19 Enhancement Tracker Sheet, or let me know, I can do it for you :)
If docs are required, just a friendly reminder that we are looking for a PR against k/website (branch dev-1.19) due by Friday, June 12, it can just be a placeholder PR at this time. Let me know if you have any questions!

[harshanarayana]

Hey @pohly, I am with the enhancements team for the v1.19 release cycle as a shadow.

The code freeze deadline for the Enhancement is Thursday, June 25. I am checking in to see if there is any k/k PR that you have already opened for this enhancement and if so, would you be able to point me in the direction of the PR so that the same can be updated in the tracking sheet

Have a wonderful day. 🖖

[zestrells]

Hi @pohly - Just a reminder that docs placeholder PR against dev-1.19 is due by June 12th. Does this enhancement require any changes to docs? If so, can you update here with a link to the PR once you have it in place? If not, please update the same, so that the tracking sheet can be updated accordingly. Thanks!

[pohly]

Doc placeholder PR: kubernetes/website#22438 (updated 2020-07-09)

I used to have the docs in a combined PR kubernetes/website#21634 but then moved to a separate one.

[harshanarayana]

Hi, @pohly

This is a follow-up to the communication that went out to k-dev today. There has been a revision to the release schedule of v1.19 as follows.

Thursday, July 9th: Week 13 - Code Freeze
Thursday, July 16th: Week 14 - Docs must be completed and reviewed
Tuesday, August 25th: Week 20 - Kubernetes v1.19.0 released
Thursday, August 27th: Week 20 - Release Retrospective

You can find the revised Schedule in the sig-release Repo

Please let me know if you have any questions. 🖖

[pohly]

This comment accidentally had a TODO list for Storage Capacity tracking. The content was moved to #1472 (comment).

[pohly]

/assign

[pohly]

• TODO* after alpha:

• check what exactly the behavior of kubelet is regarding DeletionTimestamp and DeletionGracePeriod and whether we can use it as signal for the PVC protection controller or need something else - generic ephemeral inline volumes kubernetes#92784 (comment)
• check other scheduler plugins for filtering by PVC (generic ephemeral inline volumes kubernetes#92784 (comment)), similar to https://github.com/kubernetes/kubernetes/blob/82baa26905c94398a0d19e1b1ecf54eb8acb6029/pkg/scheduler/framework/plugins/volumebinding/volume_binding.go#L80-L87

TODO before beta:

• Remove ReadOnly field (Generic ephemeral volume API kubernetes#91680 (comment))?
• Should PVC naming really be deterministic (Generic ephemeral volume API kubernetes#91680 (comment))? It simplifies access to the PVC both in code and for users (no need to search, name can be derived from pod name and volume name), but there is a certain risk that PVC names conflict in various cases which could be avoided by generating the PVC name somehow.
  • If we stick with deterministic, a helper method as replacement for pod.Name + "-" + vol.Name would be useful. Put it in k8s.io/library-go once that exists (Initialize k8s.io/component-helpers staging repository kubernetes#92507)?
• Can and should we enforce that pods are not deleted unless PVC and PV are also deleted (i.e. foreground deletion by default, make PVC the owner of the PV)? It is useful to know that the ephemeral volume is truly gone when the pod is gone. However, it may also slow down pod deletion. Needs more discussion.

[k8s-triage-robot]

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-contributor-experience at kubernetes/community.
/lifecycle stale

[jsafrane]

/remove-lifecycle stale

[xing-yang]

/milestone v1.23

[ramrodo]

Hi @pohly 👋 1.23 Docs shadow here.

This enhancement is marked as Needs Docs for the 1.23 release.

Please follow the steps detailed in the documentation to open a PR against the dev-1.23 branch in the k/website repo. This PR can be just a placeholder at this time and must be created before Thu November 18, 11:59 PM PDT.

Also, if needed take a look at Documenting for a release to familiarize yourself with the docs requirement for the release.

Thanks!

[pohly]

Final implementation PR for GA: kubernetes/kubernetes#105609
Corresponding docs PR for 1.23: kubernetes/website#30361

[gracenng]

Hi @pohly , 1.23 Enhancements Shadow here. Looks like this enhancement's code PR is merged so all good for code freeze on November 16th.

Please let me know if there's any other PR besides #105609 I should be aware of. Thanks!

[pohly]

Here's the PR marking this enhancement as implemented: #1698

However, there is one last task left: remove the feature gate definition from https://github.com/kubernetes/kubernetes/blob/712745cb6755b3a28ca12292b30d138d5f737aa6/pkg/features/kube_features.go#L171-L177 (and also docs?).

Does anyone know when that should be done?

[gracenng]

Hi @gnufied @mattsmithdatera ,

1.24 Enhancements Lead here. This enhancement is considered graduated to stable. Once the last task is complete, could you please update this enhancements's KEP status to implemented, then close this issue?

Thanks :)

[msau42]

Kubernetes deprecation policy says 2 releases for removing a feature gate: https://kubernetes.io/docs/reference/using-api/deprecation-policy/#deprecating-a-feature-or-behavior

It's also commented in the code: https://github.com/kubernetes/kubernetes/blob/712745cb6755b3a28ca12292b30d138d5f737aa6/pkg/features/kube_features.go#L897

I think you can go ahead and close this. In the past, I have seen PRs where all feature gates are cleaned up for a given release.

[wojtek-t]

I think you can go ahead and close this. In the past, I have seen PRs where all feature gates are cleaned up for a given release.

Yes - no need to keep it just for feature gate removal.

[pohly]

/close

[k8s-ci-robot]

@pohly: Closing this issue.

In response to this:

/close

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