[PodLevelResources] Update Downward API defaulting for resource limits by toVersus · Pull Request #132605 · kubernetes/kubernetes

toVersus · 2025-06-29T09:42:28Z

What type of PR is this?

/kind bug

What this PR does / why we need it:

Using the Downward API's resourceFieldRef, you can inject values specified in resources.limits, such as CPU, memory, or ephemeral storage into environment variables. Currently, when container-level resource limits were not specified and the Downward API was used to set environment variables referencing them, the node's allocatable resources were used as the fallback. With the introduction of the Pod Level Resources feature, this behavior should be updated.

If container-level resource limits are not specified, the Downward API now uses the pod-level resource limits instead.
If neither container-level nor pod-level resource limits are specified, the behavior remains unchanged. It falls back to the node's allocatable resources.

Which issue(s) this PR is related to:

Fixes: #132603
KEP: kubernetes/enhancements#2837

Special notes for your reviewer:

Does this PR introduce a user-facing change?

The fallback behavior of the Downward API's `resourceFieldRef` field has been updated to account for pod-level resources: if container-level limits are not set, pod-level limits are now used before falling back to node allocatable resources.

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

[KEP]: https://github.com/kubernetes/enhancements/issues/2837

k8s-ci-robot · 2025-06-29T09:42:37Z

Hi @toVersus. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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toVersus · 2025-06-29T09:43:24Z

/cc @ndixita

k8s-triage-robot · 2025-06-29T09:51:52Z

This PR may require API review.

If so, when the changes are ready, complete the pre-review checklist and request an API review.

Status of requested reviews is tracked in the API Review project.

ndixita · 2025-06-29T18:22:02Z

/triage accepted

toVersus · 2025-07-16T23:56:15Z

/assign @tallclair
If you have the capacity, I’d appreciate it if you could take a look at this as well.

toVersus · 2025-07-23T22:45:59Z

/test pull-kubernetes-node-kubelet-serial-podresources

ndixita · 2025-07-23T23:08:32Z

@kubernetes/sig-node-pr-reviews - can someone PTAL

dchen1107 · 2025-07-23T23:11:58Z

I did a quick review on the PR and looks good to me.

@ndixita I am approving this, but leave you to give the last lgtm for merge.

/approve

Currently, when container-level resource limits were not specified and the Downward API was used to set environment variables referencing them, the node's allocatable resources were used as the fallback. With the introduction of the Pod Level Resources feature, this behavior is updated: if container-level resource limits are not specified, the Downward API now uses the pod-level resource limits instead. If neither container-level nor pod-level resource limits are specified, the behavior remains unchanged. It falls back to the node's allocatable resources. Signed-off-by: Tsubasa Nagasawa <[email protected]>

toVersus · 2025-07-23T23:16:20Z

/test pull-kubernetes-node-kubelet-serial-podresources

msau42 · 2025-07-24T00:13:42Z

/approve

k8s-ci-robot · 2025-07-24T00:13:57Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dchen1107, msau42, toVersus

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

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Details

Needs approval from an approver in each of these files:

~~pkg/kubelet/OWNERS~~ [dchen1107]
~~staging/src/k8s.io/component-helpers/resource/OWNERS~~ [msau42]
~~test/e2e/common/OWNERS~~ [dchen1107,msau42]

Approvers can indicate their approval by writing /approve in a comment
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ndixita · 2025-07-24T18:41:27Z

/lgtm

k8s-ci-robot · 2025-07-24T18:41:34Z

LGTM label has been added.

Details

Git tree hash: 7a3a2a912510d0d204c38143ee01d9deedd8c902

HirazawaUi · 2025-07-26T09:56:21Z


 })

+var _ = SIGDescribe("Downward API", feature.PodLevelResources, func() {


It appears that we did not properly execute this test case in this PR.

PodLevelResources is a feature gate in the alpha stage. We should follow Option 1 mentioned in this email (https://groups.google.com/a/kubernetes.io/g/dev/c/uVga86nJDuI/m/gVujvOCnDwAJ) to correctly add the label for the test case, or manually trigger the dedicated e2e test job for the PodLevelResources feature (if we have already added one). Otherwise, it will be skipped during e2e test execution, Additionally, if some test job matches all features, it will execute this test case erroneously.

This e2e test case currently fails, and a related issue has been opened:
#133232

Please disregard this comment - it has already been discussed in PR #133220.

github-project-automation Bot added this to SIG Node CI/Test Board and SIG Node: code and documentation PRs Jun 29, 2025

k8s-ci-robot added sig/testing Categorizes an issue or PR as relevant to SIG Testing. and removed do-not-merge/needs-sig Indicates an issue or PR lacks a `sig/foo` label and requires one. labels Jun 29, 2025

github-project-automation Bot moved this to Triage in SIG Node: code and documentation PRs Jun 29, 2025

github-project-automation Bot moved this to Triage in SIG Node CI/Test Board Jun 29, 2025

k8s-ci-robot requested review from haircommander and rphillips June 29, 2025 09:42

k8s-ci-robot requested a review from ndixita June 29, 2025 09:43

ndixita reviewed Jun 29, 2025

View reviewed changes

Comment thread pkg/kubelet/kubelet_resources.go

k8s-ci-robot added triage/accepted Indicates an issue or PR is ready to be actively worked on. and removed needs-triage Indicates an issue or PR lacks a `triage/foo` label and requires one. labels Jun 29, 2025

toVersus force-pushed the feat/downward-api-plresources branch from adcfa0d to bedd1ef Compare June 30, 2025 00:33

k8s-ci-robot assigned tallclair Jul 16, 2025

ndixita moved this to Needs Review in SIG Node: Pod Level Resources Jul 23, 2025

ndixita added this to SIG Node: Pod Level Resources Jul 23, 2025

ndixita reviewed Jul 23, 2025

View reviewed changes

Comment thread test/e2e/common/node/downwardapi.go

toVersus force-pushed the feat/downward-api-plresources branch from 64bb683 to 98c19a8 Compare July 23, 2025 22:43

ndixita reviewed Jul 23, 2025

View reviewed changes

Comment thread pkg/kubelet/kubelet_resources.go Outdated

toVersus force-pushed the feat/downward-api-plresources branch from 98c19a8 to a82187c Compare July 23, 2025 23:15

k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Jul 24, 2025

k8s-ci-robot assigned ndixita Jul 24, 2025

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Jul 24, 2025

k8s-ci-robot merged commit bd7fb73 into kubernetes:master Jul 24, 2025
15 checks passed

k8s-ci-robot added this to the v1.34 milestone Jul 24, 2025

github-project-automation Bot moved this from Needs Review to Done in SIG Node: Pod Level Resources Jul 24, 2025

github-project-automation Bot moved this from Needs Reviewer to Done in SIG Node: code and documentation PRs Jul 24, 2025

github-project-automation Bot moved this from Archive-it to Done in SIG Node CI/Test Board Jul 24, 2025

toVersus deleted the feat/downward-api-plresources branch July 24, 2025 23:54

HirazawaUi mentioned this pull request Jul 26, 2025

[sig-node] Downward API [Feature:PodLevelResources] Downward API tests for pod level resources should provide default limits.cpu/memory from pod level resources #133232

Closed

HirazawaUi reviewed Jul 26, 2025

View reviewed changes

liggitt added this to API Reviews Dec 3, 2025

liggitt moved this to API review completed, 1.34 in API Reviews Dec 3, 2025


		})

		var _ = SIGDescribe("Downward API", feature.PodLevelResources, func() {

Conversation

toVersus commented Jun 29, 2025

What type of PR is this?

What this PR does / why we need it:

Which issue(s) this PR is related to:

Special notes for your reviewer:

Does this PR introduce a user-facing change?

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

Uh oh!

k8s-ci-robot commented Jun 29, 2025

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toVersus commented Jun 29, 2025

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k8s-triage-robot commented Jun 29, 2025

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ndixita commented Jun 29, 2025

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toVersus commented Jul 16, 2025

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toVersus commented Jul 23, 2025

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ndixita commented Jul 23, 2025

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dchen1107 commented Jul 23, 2025

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toVersus commented Jul 23, 2025

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msau42 commented Jul 24, 2025

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k8s-ci-robot commented Jul 24, 2025

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ndixita commented Jul 24, 2025

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k8s-ci-robot commented Jul 24, 2025

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HirazawaUi Jul 26, 2025 •

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