From 7fe2b7bdc25d7044384adb0e62234b88c5bda676 Mon Sep 17 00:00:00 2001
From: Martyna Grotek <martynagrotek@google.com>
Date: Mon, 6 Oct 2025 13:01:38 +0000
Subject: [PATCH 1/3] KEP-5616: Cluster Autoscaler Pod Condition

---
 keps/prod-readiness/sig-autoscaling/5616.yaml |   3 +
 .../5616-ca-pod-condition/README.md           | 845 ++++++++++++++++++
 .../5616-ca-pod-condition/kep.yaml            |  45 +
 3 files changed, 893 insertions(+)
 create mode 100644 keps/prod-readiness/sig-autoscaling/5616.yaml
 create mode 100644 keps/sig-autoscaling/5616-ca-pod-condition/README.md
 create mode 100644 keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml

diff --git a/keps/prod-readiness/sig-autoscaling/5616.yaml b/keps/prod-readiness/sig-autoscaling/5616.yaml
new file mode 100644
index 00000000000..347faea8f5b
--- /dev/null
+++ b/keps/prod-readiness/sig-autoscaling/5616.yaml
@@ -0,0 +1,3 @@
+kep-number: 5616
+alpha:
+  approver: TBD
\ No newline at end of file
diff --git a/keps/sig-autoscaling/5616-ca-pod-condition/README.md b/keps/sig-autoscaling/5616-ca-pod-condition/README.md
new file mode 100644
index 00000000000..c87ac4b4a55
--- /dev/null
+++ b/keps/sig-autoscaling/5616-ca-pod-condition/README.md
@@ -0,0 +1,845 @@
+<!--
+**Note:** When your KEP is complete, all of these comment blocks should be removed.
+
+Follow the guidelines of the [documentation style guide].
+In particular, wrap lines to a reasonable length, to make it
+easier for reviewers to cite specific portions, and to minimize diff churn on
+updates.
+
+[documentation style guide]: https://github.com/kubernetes/community/blob/master/contributors/guide/style-guide.md
+
+To get started with this template:
+
+- [ ] **Pick a hosting SIG.**
+  Make sure that the problem space is something the SIG is interested in taking
+  up. KEPs should not be checked in without a sponsoring SIG.
+- [ ] **Create an issue in kubernetes/enhancements**
+  When filing an enhancement tracking issue, please make sure to complete all
+  fields in that template. One of the fields asks for a link to the KEP. You
+  can leave that blank until this KEP is filed, and then go back to the
+  enhancement and add the link.
+- [ ] **Make a copy of this template directory.**
+  Copy this template into the owning SIG's directory and name it
+  `NNNN-short-descriptive-title`, where `NNNN` is the issue number (with no
+  leading-zero padding) assigned to your enhancement above.
+- [ ] **Fill out as much of the kep.yaml file as you can.**
+  At minimum, you should fill in the "Title", "Authors", "Owning-sig",
+  "Status", and date-related fields.
+- [ ] **Fill out this file as best you can.**
+  At minimum, you should fill in the "Summary" and "Motivation" sections.
+  These should be easy if you've preflighted the idea of the KEP with the
+  appropriate SIG(s).
+- [ ] **Create a PR for this KEP.**
+  Assign it to people in the SIG who are sponsoring this process.
+- [ ] **Merge early and iterate.**
+  Avoid getting hung up on specific details and instead aim to get the goals of
+  the KEP clarified and merged quickly. The best way to do this is to just
+  start with the high-level sections and fill out details incrementally in
+  subsequent PRs.
+
+Just because a KEP is merged does not mean it is complete or approved. Any KEP
+marked as `provisional` is a working document and subject to change. You can
+denote sections that are under active debate as follows:
+
+```
+<<[UNRESOLVED optional short context or usernames ]>>
+Stuff that is being argued.
+<<[/UNRESOLVED]>>
+```
+
+When editing KEPS, aim for tightly-scoped, single-topic PRs to keep discussions
+focused. If you disagree with what is already in a document, open a new PR
+with suggested changes.
+
+One KEP corresponds to one "feature" or "enhancement" for its whole lifecycle.
+You do not need a new KEP to move from beta to GA, for example. If
+new details emerge that belong in the KEP, edit the KEP. Once a feature has become
+"implemented", major changes should get new KEPs.
+
+The canonical place for the latest set of instructions (and the likely source
+of this file) is [here](/keps/NNNN-kep-template/README.md).
+
+**Note:** Any PRs to move a KEP to `implementable`, or significant changes once
+it is marked `implementable`, must be approved by each of the KEP approvers.
+If none of those approvers are still appropriate, then changes to that list
+should be approved by the remaining approvers and/or the owning SIG (or
+SIG Architecture for cross-cutting KEPs).
+-->
+# KEP-5616: Cluster Autoscaler Pod Condition
+
+<!--
+This is the title of your KEP. Keep it short, simple, and descriptive. A good
+title can help communicate what the KEP is and should be considered as part of
+any review.
+-->
+
+<!--
+A table of contents is helpful for quickly jumping to sections of a KEP and for
+highlighting any additional information provided beyond the standard KEP
+template.
+
+Ensure the TOC is wrapped with
+  <code>&lt;!-- toc --&rt;&lt;!-- /toc --&rt;</code>
+tags, and then generate with `hack/update-toc.sh`.
+-->
+
+<!-- toc -->
+- [Release Signoff Checklist](#release-signoff-checklist)
+- [Summary](#summary)
+- [Motivation](#motivation)
+  - [Goals](#goals)
+  - [Non-Goals](#non-goals)
+- [Proposal](#proposal)
+  - [User Stories (Optional)](#user-stories-optional)
+    - [Story 1](#story-1)
+    - [Story 2](#story-2)
+  - [Notes/Constraints/Caveats (Optional)](#notesconstraintscaveats-optional)
+  - [Risks and Mitigations](#risks-and-mitigations)
+- [Design Details](#design-details)
+  - [Test Plan](#test-plan)
+      - [Prerequisite testing updates](#prerequisite-testing-updates)
+      - [Unit tests](#unit-tests)
+      - [Integration tests](#integration-tests)
+      - [e2e tests](#e2e-tests)
+  - [Graduation Criteria](#graduation-criteria)
+  - [Upgrade / Downgrade Strategy](#upgrade--downgrade-strategy)
+  - [Version Skew Strategy](#version-skew-strategy)
+- [Production Readiness Review Questionnaire](#production-readiness-review-questionnaire)
+  - [Feature Enablement and Rollback](#feature-enablement-and-rollback)
+  - [Rollout, Upgrade and Rollback Planning](#rollout-upgrade-and-rollback-planning)
+  - [Monitoring Requirements](#monitoring-requirements)
+  - [Dependencies](#dependencies)
+  - [Scalability](#scalability)
+  - [Troubleshooting](#troubleshooting)
+- [Implementation History](#implementation-history)
+- [Drawbacks](#drawbacks)
+- [Alternatives](#alternatives)
+- [Infrastructure Needed (Optional)](#infrastructure-needed-optional)
+<!-- /toc -->
+
+## Release Signoff Checklist
+
+<!--
+**ACTION REQUIRED:** In order to merge code into a release, there must be an
+issue in [kubernetes/enhancements] referencing this KEP and targeting a release
+milestone **before the [Enhancement Freeze](https://git.k8s.io/sig-release/releases)
+of the targeted release**.
+
+For enhancements that make changes to code or processes/procedures in core
+Kubernetes—i.e., [kubernetes/kubernetes], we require the following Release
+Signoff checklist to be completed.
+
+Check these off as they are completed for the Release Team to track. These
+checklist items _must_ be updated for the enhancement to be released.
+-->
+
+Items marked with (R) are required *prior to targeting to a milestone / release*.
+
+- [ ] (R) Enhancement issue in release milestone, which links to KEP dir in [kubernetes/enhancements] (not the initial KEP PR)
+- [ ] (R) KEP approvers have approved the KEP status as `implementable`
+- [ ] (R) Design details are appropriately documented
+- [ ] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input (including test refactors)
+  - [ ] e2e Tests for all Beta API Operations (endpoints)
+  - [ ] (R) Ensure GA e2e tests meet requirements for [Conformance Tests](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md)
+  - [ ] (R) Minimum Two Week Window for GA e2e tests to prove flake free
+- [ ] (R) Graduation criteria is in place
+  - [ ] (R) [all GA Endpoints](https://github.com/kubernetes/community/pull/1806) must be hit by [Conformance Tests](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/conformance-tests.md) within one minor version of promotion to GA
+- [ ] (R) Production readiness review completed
+- [ ] (R) Production readiness review approved
+- [ ] "Implementation History" section is up-to-date for milestone
+- [ ] User-facing documentation has been created in [kubernetes/website], for publication to [kubernetes.io]
+- [ ] Supporting documentation—e.g., additional design documents, links to mailing list discussions/SIG meetings, relevant PRs/issues, release notes
+
+<!--
+**Note:** This checklist is iterative and should be reviewed and updated every time this enhancement is being considered for a milestone.
+-->
+
+[kubernetes.io]: https://kubernetes.io/
+[kubernetes/enhancements]: https://git.k8s.io/enhancements
+[kubernetes/kubernetes]: https://git.k8s.io/kubernetes
+[kubernetes/website]: https://git.k8s.io/website
+
+## Summary
+
+Cluster Autoscaler does not provide reliable observability for clients. 
+
+k8s events are [best effort and it is discouraged to use them for any automations](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/event-style-guide.md). Additionaly [cache is disbaled](https://github.com/kubernetes/kubernetes/issues/131897) for them.
+
+This proposal introduces new pod condition owned by Cluster Autoscaler, which will provide information about scale up (being in progress or not attepmted).
+
+
+## Motivation
+
+<!--
+This section is for explicitly listing the motivation, goals, and non-goals of
+this KEP.  Describe why the change is important and the benefits to users. The
+motivation section can optionally provide links to [experience reports] to
+demonstrate the interest in a KEP within the wider Kubernetes community.
+
+[experience reports]: https://github.com/golang/go/wiki/ExperienceReports
+-->
+
+### Goals
+
+<!--
+List the specific goals of the KEP. What is it trying to achieve? How will we
+know that this has succeeded?
+-->
+
+  * Provide information regarding scale up for particular pod, which can be consumed by automations and other components (eg. scheduler: https://github.com/kubernetes/enhancements/issues/3990).
+  * Improve observability and debuggability for human operators.
+  * Introduce realiable replacement for k8s events: TriggeredScaleUp and NotTriggerScaleUp.
+
+### Non-Goals
+
+  * Changing how Cluster Autoscaler is handling unschedulable pods.
+
+
+## Proposal
+
+<!--
+This is where we get down to the specifics of what the proposal actually is.
+This should have enough detail that reviewers can understand exactly what
+you're proposing, but should not include things like API designs or
+implementation. What is the desired outcome and how do we measure success?.
+The "Design Details" section below is for the real
+nitty-gritty.
+-->
+
+Introduce new pod condition type `NodeProvisioningInProgress`.
+- `NodeProvisioningInProgress: True` (with empty reason) corresponding to todays `TiggeredScaleUp` event, meaning CA decided to scale up cluster to make place for this pod.
+- `NodeProvisioningInProgress: False`  corresponding to todays `NotTriggerScaleUp` event, meaning CA couldn't find node group that can be scaled up to make this pod schedulable.
+
+In case of failure, we would change reason to `Error`. After CA runs out of scale up options (all attempted failed) we would change the condition to `NodeProvisioningInProgress: False`.
+
+
+### User Stories (Optional)
+
+<!--
+Detail the things that people will be able to do if this KEP is implemented.
+Include as much detail as possible so that people can understand the "how" of
+the system. The goal here is to make this feel real for users without getting
+bogged down.
+-->
+
+#### Story 1
+
+As a user, I want to have an easy and reliable way to investigate why my pods are stuck in the Pending phase.
+
+#### Story 2
+
+### Notes/Constraints/Caveats (Optional)
+
+<!--
+What are the caveats to the proposal?
+What are some important details that didn't come across above?
+Go in to as much detail as necessary here.
+This might be a good place to talk about core concepts and how they relate.
+-->
+
+### Risks and Mitigations
+
+<!--
+What are the risks of this proposal, and how do we mitigate? Think broadly.
+For example, consider both security and how this will impact the larger
+Kubernetes ecosystem.
+
+How will security be reviewed, and by whom?
+
+How will UX be reviewed, and by whom?
+
+Consider including folks who also work outside the SIG or subproject.
+-->
+
+## Design Details
+
+<!--
+This section should contain enough information that the specifics of your
+change are understandable. This may include API specs (though not always
+required) or even code snippets. If there's any ambiguity about HOW your
+proposal will be implemented, this is the place to discuss them.
+-->
+
+We would emit them from the same place as corresponding k8s events, which is `EventingScaleUpStatusProcessor`.
+
+ScaleUpResult                 | Pod condition type & status       | Pod condition reason
+:---------------------------- | :-------------------------------- | :-------------------
+ScaleUpSuccessful             | NodeProvisioningInProgress: True  |         
+ScaleUpError                  | NodeProvisioningInProgress: True  | ...Error 
+ScaleUpNoOptionsAvailable     | NodeProvisioningInProgress: False | NoOptionsAvailable
+ScaleUpNotTried               | NodeProvisioningInProgress: False | NotTried
+ScaleUpInCooldown             | NodeProvisioningInProgress: False | InCooldown
+ScaleUpLimitedByMaxNodesTotal | NodeProvisioningInProgress: False | LimitedByMaxNodesTotal
+
+We distinguish following ScaleUpErrors (`errors.AutoscalerError`):
+- CloudProviderError, which is an error related to underlying infrastructure
+- ApiCallError, which is an error related to communication with k8s API server
+- InternalError, which is an error inside Cluster Autoscaler
+- TransientError, which is an error that causes us to skip a single loop, but does not require any additional action.
+- ConfigurationError, which is an error related to bad configuration provided by a user.
+- NodeGroupDoesNotExistError, which signifies that a NodeGroupdoes not exist.
+
+And we would have correspoding reasons in new pod condition.
+
+In future we could consider using `SkippedReasons` to fill ScaleUpNoOptionsAvailable with more details, but the message would need to be aggregated somehow because they are per node group. 
+
+Some examples of `SkippedReasons`:
+- BackoffReason - "in backoff after failed scale-up"
+- MaxLimitReachedReason - "max node group size reached"
+- NotReadyReason - "not ready for scale-up"
+
+
+### Test Plan
+
+<!--
+**Note:** *Not required until targeted at a release.*
+The goal is to ensure that we don't accept enhancements with inadequate testing.
+
+All code is expected to have adequate tests (eventually with coverage
+expectations). Please adhere to the [Kubernetes testing guidelines][testing-guidelines]
+when drafting this test plan.
+
+[testing-guidelines]: https://git.k8s.io/community/contributors/devel/sig-testing/testing.md
+-->
+
+[ ] I/we understand the owners of the involved components may require updates to
+existing tests to make this code solid enough prior to committing the changes necessary
+to implement this enhancement.
+
+##### Prerequisite testing updates
+
+<!--
+Based on reviewers feedback describe what additional tests need to be added prior
+implementing this enhancement to ensure the enhancements have also solid foundations.
+-->
+
+##### Unit tests
+
+<!--
+In principle every added code should have complete unit test coverage, so providing
+the exact set of tests will not bring additional value.
+However, if complete unit test coverage is not possible, explain the reason of it
+together with explanation why this is acceptable.
+-->
+
+<!--
+Additionally, for Alpha try to enumerate the core package you will be touching
+to implement this enhancement and provide the current unit coverage for those
+in the form of:
+- <package>: <date> - <current test coverage>
+The data can be easily read from:
+https://testgrid.k8s.io/sig-testing-canaries#ci-kubernetes-coverage-unit
+
+This can inform certain test coverage improvements that we want to do before
+extending the production code to implement this enhancement.
+-->
+
+- `<package>`: `<date>` - `<test coverage>`
+
+##### Integration tests
+
+<!--
+Integration tests are contained in https://git.k8s.io/kubernetes/test/integration.
+Integration tests allow control of the configuration parameters used to start the binaries under test.
+This is different from e2e tests which do not allow configuration of parameters.
+Doing this allows testing non-default options and multiple different and potentially conflicting command line options.
+For more details, see https://github.com/kubernetes/community/blob/master/contributors/devel/sig-testing/testing-strategy.md
+
+If integration tests are not necessary or useful, explain why.
+-->
+
+<!--
+This question should be filled when targeting a release.
+For Alpha, describe what tests will be added to ensure proper quality of the enhancement.
+
+For Beta and GA, document that tests have been written,
+have been executed regularly, and have been stable.
+This can be done with:
+- permalinks to the GitHub source code
+- links to the periodic job (typically https://testgrid.k8s.io/sig-release-master-blocking#integration-master), filtered by the test name
+- a search in the Kubernetes bug triage tool (https://storage.googleapis.com/k8s-triage/index.html)
+-->
+
+- [test name](https://github.com/kubernetes/kubernetes/blob/2334b8469e1983c525c0c6382125710093a25883/test/integration/...): [integration master](https://testgrid.k8s.io/sig-release-master-blocking#integration-master?include-filter-by-regex=MyCoolFeature), [triage search](https://storage.googleapis.com/k8s-triage/index.html?test=MyCoolFeature)
+
+##### e2e tests
+
+<!--
+This question should be filled when targeting a release.
+For Alpha, describe what tests will be added to ensure proper quality of the enhancement.
+
+For Beta and GA, document that tests have been written,
+have been executed regularly, and have been stable.
+This can be done with:
+- permalinks to the GitHub source code
+- links to the periodic job (typically a job owned by the SIG responsible for the feature), filtered by the test name
+- a search in the Kubernetes bug triage tool (https://storage.googleapis.com/k8s-triage/index.html)
+
+We expect no non-infra related flakes in the last month as a GA graduation criteria.
+If e2e tests are not necessary or useful, explain why.
+-->
+
+- [test name](https://github.com/kubernetes/kubernetes/blob/2334b8469e1983c525c0c6382125710093a25883/test/e2e/...): [SIG ...](https://testgrid.k8s.io/sig-...?include-filter-by-regex=MyCoolFeature), [triage search](https://storage.googleapis.com/k8s-triage/index.html?test=MyCoolFeature)
+
+### Graduation Criteria
+
+<!--
+**Note:** *Not required until targeted at a release.*
+
+Define graduation milestones.
+
+These may be defined in terms of API maturity, [feature gate] graduations, or as
+something else. The KEP should keep this high-level with a focus on what
+signals will be looked at to determine graduation.
+
+Consider the following in developing the graduation criteria for this enhancement:
+- [Maturity levels (`alpha`, `beta`, `stable`)][maturity-levels]
+- [Feature gate][feature gate] lifecycle
+- [Deprecation policy][deprecation-policy]
+
+Clearly define what graduation means by either linking to the [API doc
+definition](https://kubernetes.io/docs/concepts/overview/kubernetes-api/#api-versioning)
+or by redefining what graduation means.
+
+In general we try to use the same stages (alpha, beta, GA), regardless of how the
+functionality is accessed.
+
+[feature gate]: https://git.k8s.io/community/contributors/devel/sig-architecture/feature-gates.md
+[maturity-levels]: https://git.k8s.io/community/contributors/devel/sig-architecture/api_changes.md#alpha-beta-and-stable-versions
+[deprecation-policy]: https://kubernetes.io/docs/reference/using-api/deprecation-policy/
+
+Below are some examples to consider, in addition to the aforementioned [maturity levels][maturity-levels].
+
+#### Alpha
+
+- Feature implemented behind a feature flag
+- Initial e2e tests completed and enabled
+
+#### Beta
+
+- Gather feedback from developers and surveys
+- Complete features A, B, C
+- Additional tests are in Testgrid and linked in KEP
+- More rigorous forms of testing—e.g., downgrade tests and scalability tests
+- All functionality completed
+- All security enforcement completed
+- All monitoring requirements completed
+- All testing requirements completed
+- All known pre-release issues and gaps resolved
+
+**Note:** Beta criteria must include all functional, security, monitoring, and testing requirements along with resolving all issues and gaps identified
+
+#### GA
+
+- N examples of real-world usage
+- N installs
+- Allowing time for feedback
+- All issues and gaps identified as feedback during beta are resolved
+
+**Note:** GA criteria must not include any functional, security, monitoring, or testing requirements.  Those must be beta requirements.
+
+**Note:** Generally we also wait at least two releases between beta and
+GA/stable, because there's no opportunity for user feedback, or even bug reports,
+in back-to-back releases.
+
+**For non-optional features moving to GA, the graduation criteria must include
+[conformance tests].**
+
+[conformance tests]: https://git.k8s.io/community/contributors/devel/sig-architecture/conformance-tests.md
+
+#### Deprecation
+
+<!--
+- Announce deprecation and support policy of the existing flag
+- Two versions passed since introducing the functionality that deprecates the flag (to address version skew)
+- Address feedback on usage/changed behavior, provided on GitHub issues
+- Deprecate the flag
+-->
+
+### Upgrade / Downgrade Strategy
+
+<!--
+If applicable, how will the component be upgraded and downgraded? Make sure
+this is in the test plan.
+
+Consider the following in developing an upgrade/downgrade strategy for this
+enhancement:
+- What changes (in invocations, configurations, API use, etc.) is an existing
+  cluster required to make on upgrade, in order to maintain previous behavior?
+- What changes (in invocations, configurations, API use, etc.) is an existing
+  cluster required to make on upgrade, in order to make use of the enhancement?
+-->
+
+### Version Skew Strategy
+
+<!--
+If applicable, how will the component handle version skew with other
+components? What are the guarantees? Make sure this is in the test plan.
+
+Consider the following in developing a version skew strategy for this
+enhancement:
+- Does this enhancement involve coordinating behavior in the control plane and nodes?
+- How does an n-3 kubelet or kube-proxy without this feature available behave when this feature is used?
+- How does an n-1 kube-controller-manager or kube-scheduler without this feature available behave when this feature is used?
+- Will any other components on the node change? For example, changes to CSI,
+  CRI or CNI may require updating that component before the kubelet.
+-->
+
+## Production Readiness Review Questionnaire
+
+<!--
+
+Production readiness reviews are intended to ensure that features merging into
+Kubernetes are observable, scalable and supportable; can be safely operated in
+production environments, and can be disabled or rolled back in the event they
+cause increased failures in production. See more in the PRR KEP at
+https://git.k8s.io/enhancements/keps/sig-architecture/1194-prod-readiness.
+
+The production readiness review questionnaire must be completed and approved
+for the KEP to move to `implementable` status and be included in the release.
+
+In some cases, the questions below should also have answers in `kep.yaml`. This
+is to enable automation to verify the presence of the review, and to reduce review
+burden and latency.
+
+The KEP must have a approver from the
+[`prod-readiness-approvers`](http://git.k8s.io/enhancements/OWNERS_ALIASES)
+team. Please reach out on the
+[#prod-readiness](https://kubernetes.slack.com/archives/CPNHUMN74) channel if
+you need any help or guidance.
+-->
+
+### Feature Enablement and Rollback
+
+<!--
+This section must be completed when targeting alpha to a release.
+-->
+
+###### How can this feature be enabled / disabled in a live cluster?
+
+<!--
+Pick one of these and delete the rest.
+
+Documentation is available on [feature gate lifecycle] and expectations, as
+well as the [existing list] of feature gates.
+
+[feature gate lifecycle]: https://git.k8s.io/community/contributors/devel/sig-architecture/feature-gates.md
+[existing list]: https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/
+-->
+
+- [x] Feature gate (also fill in values in `kep.yaml`)
+  - Feature gate name: `ScaleUpObservability` with values:
+    - `EventsOnly` -  current state,
+    - `EventsAndConditions` - produce both - we could turn it on scalability tests and assess the impact on the overall performance,
+    - `ConditionsOnly` - produce only new pod conditions.
+  - Components depending on the feature gate: `cluster-autoscaler`.
+
+
+###### Does enabling the feature change any default behavior?
+
+No, by default, CA will continue to use the `EventsOnly` for the scale up observability. 
+
+###### Can the feature be disabled once it has been enabled (i.e. can we roll back the enablement)?
+
+<!--
+Describe the consequences on existing workloads (e.g., if this is a runtime
+feature, can it break the existing applications?).
+
+Feature gates are typically disabled by setting the flag to `false` and
+restarting the component. No other changes should be necessary to disable the
+feature.
+
+NOTE: Also set `disable-supported` to `true` or `false` in `kep.yaml`.
+-->
+
+Yes.
+
+###### What happens if we reenable the feature if it was previously rolled back?
+
+There should be no problems.
+
+###### Are there any tests for feature enablement/disablement?
+
+<!--
+The e2e framework does not currently support enabling or disabling feature
+gates. However, unit tests in each component dealing with managing data, created
+with and without the feature, are necessary. At the very least, think about
+conversion tests if API types are being modified.
+
+Additionally, for features that are introducing a new API field, unit tests that
+are exercising the `switch` of feature gate itself (what happens if I disable a
+feature gate after having objects written with the new field) are also critical.
+You can take a look at one potential example of such test in:
+https://github.com/kubernetes/kubernetes/pull/97058/files#diff-7826f7adbc1996a05ab52e3f5f02429e94b68ce6bce0dc534d1be636154fded3R246-R282
+-->
+
+No, but they will be added.
+
+### Rollout, Upgrade and Rollback Planning
+
+<!--
+This section must be completed when targeting beta to a release.
+-->
+
+###### How can a rollout or rollback fail? Can it impact already running workloads?
+
+<!--
+Try to be as paranoid as possible - e.g., what if some components will restart
+mid-rollout?
+
+Be sure to consider highly-available clusters, where, for example,
+feature flags will be enabled on some API servers and not others during the
+rollout. Similarly, consider large clusters and how enablement/disablement
+will rollout across nodes.
+-->
+
+Enablement and disablement of the feature should not affect already running workloads.
+
+###### What specific metrics should inform a rollback?
+
+<!--
+What signals should users be paying attention to when the feature is young
+that might indicate a serious problem?
+-->
+
+###### Were upgrade and rollback tested? Was the upgrade->downgrade->upgrade path tested?
+
+<!--
+Describe manual testing that was done and the outcomes.
+Longer term, we may want to require automated upgrade/rollback tests, but we
+are missing a bunch of machinery and tooling and can't do that now.
+-->
+
+###### Is the rollout accompanied by any deprecations and/or removals of features, APIs, fields of API types, flags, etc.?
+
+<!--
+Even if applying deprecation policies, they may still surprise some users.
+-->
+
+### Monitoring Requirements
+
+<!--
+This section must be completed when targeting beta to a release.
+
+For GA, this section is required: approvers should be able to confirm the
+previous answers based on experience in the field.
+-->
+
+###### How can an operator determine if the feature is in use by workloads?
+
+<!--
+Ideally, this should be a metric. Operations against the Kubernetes API (e.g.,
+checking if there are objects with field X set) may be a last resort. Avoid
+logs or events for this purpose.
+-->
+
+###### How can someone using this feature know that it is working for their instance?
+
+<!--
+For instance, if this is a pod-related feature, it should be possible to determine if the feature is functioning properly
+for each individual pod.
+Pick one more of these and delete the rest.
+Please describe all items visible to end users below with sufficient detail so that they can verify correct enablement
+and operation of this feature.
+Recall that end users cannot usually observe component logs or access metrics.
+-->
+
+For pods in `Pending` phase, with condition:
+```yaml
+    status: "False"
+    type: PodScheduled
+    reason: "Unschedulable"
+```
+should also have new `NodeProvisioningInProgress` condition.
+
+
+###### What are the reasonable SLOs (Service Level Objectives) for the enhancement?
+
+<!--
+This is your opportunity to define what "normal" quality of service looks like
+for a feature.
+
+It's impossible to provide comprehensive guidance, but at the very
+high level (needs more precise definitions) those may be things like:
+  - per-day percentage of API calls finishing with 5XX errors <= 1%
+  - 99% percentile over day of absolute value from (job creation time minus expected
+    job creation time) for cron job <= 10%
+  - 99.9% of /health requests per day finish with 200 code
+
+These goals will help you determine what you need to measure (SLIs) in the next
+question.
+-->
+
+###### What are the SLIs (Service Level Indicators) an operator can use to determine the health of the service?
+
+<!--
+Pick one more of these and delete the rest.
+-->
+
+- [ ] Metrics
+  - Metric name:
+  - [Optional] Aggregation method:
+  - Components exposing the metric:
+- [ ] Other (treat as last resort)
+  - Details:
+
+###### Are there any missing metrics that would be useful to have to improve observability of this feature?
+
+<!--
+Describe the metrics themselves and the reasons why they weren't added (e.g., cost,
+implementation difficulties, etc.).
+-->
+
+### Dependencies
+
+<!--
+This section must be completed when targeting beta to a release.
+-->
+
+###### Does this feature depend on any specific services running in the cluster?
+
+<!--
+Think about both cluster-level services (e.g. metrics-server) as well
+as node-level agents (e.g. specific version of CRI). Focus on external or
+optional services that are needed. For example, if this feature depends on
+a cloud provider API, or upon an external software-defined storage or network
+control plane.
+
+For each of these, fill in the following—thinking about running existing user workloads
+and creating new ones, as well as about cluster-level services (e.g. DNS):
+  - [Dependency name]
+    - Usage description:
+      - Impact of its outage on the feature:
+      - Impact of its degraded performance or high-error rates on the feature:
+-->
+No.
+
+### Scalability
+
+<!--
+For alpha, this section is encouraged: reviewers should consider these questions
+and attempt to answer them.
+
+For beta, this section is required: reviewers must answer these questions.
+
+For GA, this section is required: approvers should be able to confirm the
+previous answers based on experience in the field.
+-->
+
+###### Will enabling / using this feature result in any new API calls?
+
+Yes, 
+  - PATCH pods
+  - estimated throughput: in a scale-up scenario 2x per pod
+  - originating component: Cluster Autoscaler
+
+###### Will enabling / using this feature result in introducing new API types?
+
+No.
+
+###### Will enabling / using this feature result in any new calls to the cloud provider?
+
+No.
+
+###### Will enabling / using this feature result in increasing size or count of the existing API objects?
+
+<!--
+Describe them, providing:
+  - API type(s):
+  - Estimated increase in size: (e.g., new annotation of size 32B)
+  - Estimated amount of new objects: (e.g., new Object X for every existing Pod)
+-->
+
+###### Will enabling / using this feature result in increasing time taken by any operations covered by existing SLIs/SLOs?
+
+<!--
+Look at the [existing SLIs/SLOs].
+
+Think about adding additional work or introducing new steps in between
+(e.g. need to do X to start a container), etc. Please describe the details.
+
+[existing SLIs/SLOs]: https://git.k8s.io/community/sig-scalability/slos/slos.md#kubernetes-slisslos
+-->
+
+###### Will enabling / using this feature result in non-negligible increase of resource usage (CPU, RAM, disk, IO, ...) in any components?
+
+<!--
+Things to keep in mind include: additional in-memory state, additional
+non-trivial computations, excessive access to disks (including increased log
+volume), significant amount of data sent and/or received over network, etc.
+This through this both in small and large cases, again with respect to the
+[supported limits].
+
+[supported limits]: https://git.k8s.io/community//sig-scalability/configs-and-limits/thresholds.md
+-->
+
+###### Can enabling / using this feature result in resource exhaustion of some node resources (PIDs, sockets, inodes, etc.)?
+
+No.
+
+### Troubleshooting
+
+<!--
+This section must be completed when targeting beta to a release.
+
+For GA, this section is required: approvers should be able to confirm the
+previous answers based on experience in the field.
+
+The Troubleshooting section currently serves the `Playbook` role. We may consider
+splitting it into a dedicated `Playbook` document (potentially with some monitoring
+details). For now, we leave it here.
+-->
+
+###### How does this feature react if the API server and/or etcd is unavailable?
+
+###### What are other known failure modes?
+
+<!--
+For each of them, fill in the following information by copying the below template:
+  - [Failure mode brief description]
+    - Detection: How can it be detected via metrics? Stated another way:
+      how can an operator troubleshoot without logging into a master or worker node?
+    - Mitigations: What can be done to stop the bleeding, especially for already
+      running user workloads?
+    - Diagnostics: What are the useful log messages and their required logging
+      levels that could help debug the issue?
+      Not required until feature graduated to beta.
+    - Testing: Are there any tests for failure mode? If not, describe why.
+-->
+
+###### What steps should be taken if SLOs are not being met to determine the problem?
+
+## Implementation History
+
+<!--
+Major milestones in the lifecycle of a KEP should be tracked in this section.
+Major milestones might include:
+- the `Summary` and `Motivation` sections being merged, signaling SIG acceptance
+- the `Proposal` section being merged, signaling agreement on a proposed design
+- the date implementation started
+- the first Kubernetes release where an initial version of the KEP was available
+- the version of Kubernetes where the KEP graduated to general availability
+- when the KEP was retired or superseded
+-->
+
+## Drawbacks
+
+<!--
+Why should this KEP _not_ be implemented?
+-->
+
+## Alternatives
+
+<!--
+What other approaches did you consider, and why did you rule them out? These do
+not need to be as detailed as the proposal, but should include enough
+information to express the idea and why it was not acceptable.
+-->
+
+## Infrastructure Needed (Optional)
+
+<!--
+Use this section if you need things from the project/SIG. Examples include a
+new subproject, repos requested, or GitHub details. Listing these here allows a
+SIG to get the process for these resources started right away.
+-->
diff --git a/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml b/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml
new file mode 100644
index 00000000000..b7a5d39ca2f
--- /dev/null
+++ b/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml
@@ -0,0 +1,45 @@
+title: Cluster Autoscaler Pod Conditions
+kep-number: 5616
+authors:
+  - "@MartynaGrotek"
+owning-sig: sig-autoscaling
+participating-sigs:
+  - sig-autoscaling
+  - sig-scheduling
+status: provisional # |implementable|implemented|deferred|rejected|withdrawn|replaced
+creation-date: 2025-10-06
+reviewers:
+  - TBD
+approvers:
+  - TBD
+
+see-also:
+  - "/keps/sig-scheduling/3990-pod-topology-spread-fallback-mode"
+
+# The target maturity stage in the current dev cycle for this KEP.
+# If the purpose of this KEP is to deprecate a user-visible feature
+# and a Deprecated feature gates are added, they should be deprecated|disabled|removed.
+stage: alpha
+
+# The most recent milestone for which work toward delivery of this KEP has been
+# done. This can be the current (upcoming) milestone, if it is being actively
+# worked on.
+latest-milestone: "v1.35"
+
+# The milestone at which this feature was, or is targeted to be, at each stage.
+milestone:
+  alpha: "v1.35"
+  beta: "v1.36"
+  stable: "v1.37"
+
+# The following PRR answers are required at alpha release
+# List the feature gate name and the components for which it must be enabled
+feature-gates:
+  - name: ScaleUpObservability
+    components:
+      - cluster-autoscaler
+disable-supported: true
+
+# The following PRR answers are required at beta release
+metrics:
+  - TBD

From b808320a0109a59c9c429efcfe605c0ac81f8d0a Mon Sep 17 00:00:00 2001
From: Martyna Grotek <martynagrotek@google.com>
Date: Mon, 13 Oct 2025 19:43:11 +0000
Subject: [PATCH 2/3] Get rid of CA-specific parts

---
 .../5616-ca-pod-condition/README.md           | 58 ++++++++-----------
 1 file changed, 24 insertions(+), 34 deletions(-)

diff --git a/keps/sig-autoscaling/5616-ca-pod-condition/README.md b/keps/sig-autoscaling/5616-ca-pod-condition/README.md
index c87ac4b4a55..5e210e9940e 100644
--- a/keps/sig-autoscaling/5616-ca-pod-condition/README.md
+++ b/keps/sig-autoscaling/5616-ca-pod-condition/README.md
@@ -207,10 +207,14 @@ nitty-gritty.
 -->
 
 Introduce new pod condition type `NodeProvisioningInProgress`.
-- `NodeProvisioningInProgress: True` (with empty reason) corresponding to todays `TiggeredScaleUp` event, meaning CA decided to scale up cluster to make place for this pod.
-- `NodeProvisioningInProgress: False`  corresponding to todays `NotTriggerScaleUp` event, meaning CA couldn't find node group that can be scaled up to make this pod schedulable.
 
-In case of failure, we would change reason to `Error`. After CA runs out of scale up options (all attempted failed) we would change the condition to `NodeProvisioningInProgress: False`.
+`NodeProvisioningInProgress: True` denotes that cluster autoscaler attempts to provision node  for a pod. It would correspond to todays `TiggeredScaleUp` k8s event. In case of failure, but some options still being available, it will stay `True`, but the reason will be `ProvisioningAttemptFailed`. 
+
+`NodeProvisioningInProgress: False` means no provisiong attempted for a pod at this moment. It would correspond to todays `NotTriggerScaleUp` event.
+
+Condition won't be cleared after successful scheduling of a pod.
+
+Autoscaler-specific details could be stored in `message` field in [pod condition](https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#pod-conditions).
 
 
 ### User Stories (Optional)
@@ -224,10 +228,14 @@ bogged down.
 
 #### Story 1
 
-As a user, I want to have an easy and reliable way to investigate why my pods are stuck in the Pending phase.
+As a user, I want to be able to setup automation detecting no provisioning for a pod happening at the moment.
 
 #### Story 2
 
+*From [KEP-3990: PodTopologySpread DoNotSchedule-to-ScheduleAnyway fallback mode](https://github.com/kubernetes/enhancements/issues/3990):*
+
+Scheduler should know which unschedulable Pod(s) don't trigger creation of nodes to fall back to `ScheduleAnyway` for Pod Topology Spread.
+
 ### Notes/Constraints/Caveats (Optional)
 
 <!--
@@ -237,6 +245,9 @@ Go in to as much detail as necessary here.
 This might be a good place to talk about core concepts and how they relate.
 -->
 
+Pod condition can't be used as a [field predicate](https://kubernetes.io/docs/concepts/overview/working-with-objects/field-selectors/#list-of-supported-fields) while listing relevant pods, but `status.phase==Pending` can as a server side pre-filtering. After that client side filtering can be implemented based on needs.
+
+
 ### Risks and Mitigations
 
 <!--
@@ -260,33 +271,15 @@ required) or even code snippets. If there's any ambiguity about HOW your
 proposal will be implemented, this is the place to discuss them.
 -->
 
-We would emit them from the same place as corresponding k8s events, which is `EventingScaleUpStatusProcessor`.
-
-ScaleUpResult                 | Pod condition type & status       | Pod condition reason
-:---------------------------- | :-------------------------------- | :-------------------
-ScaleUpSuccessful             | NodeProvisioningInProgress: True  |         
-ScaleUpError                  | NodeProvisioningInProgress: True  | ...Error 
-ScaleUpNoOptionsAvailable     | NodeProvisioningInProgress: False | NoOptionsAvailable
-ScaleUpNotTried               | NodeProvisioningInProgress: False | NotTried
-ScaleUpInCooldown             | NodeProvisioningInProgress: False | InCooldown
-ScaleUpLimitedByMaxNodesTotal | NodeProvisioningInProgress: False | LimitedByMaxNodesTotal
-
-We distinguish following ScaleUpErrors (`errors.AutoscalerError`):
-- CloudProviderError, which is an error related to underlying infrastructure
-- ApiCallError, which is an error related to communication with k8s API server
-- InternalError, which is an error inside Cluster Autoscaler
-- TransientError, which is an error that causes us to skip a single loop, but does not require any additional action.
-- ConfigurationError, which is an error related to bad configuration provided by a user.
-- NodeGroupDoesNotExistError, which signifies that a NodeGroupdoes not exist.
-
-And we would have correspoding reasons in new pod condition.
+When unschedulable pod is noticed by node autoscaler, there are two options (at each point in time):
+1. attempt to help it (`NodeProvisioningInProgress: True`)
+2. do nothing (`NodeProvisioningInProgress: False`)
 
-In future we could consider using `SkippedReasons` to fill ScaleUpNoOptionsAvailable with more details, but the message would need to be aggregated somehow because they are per node group. 
+Transition is possible in both directions:
+- True -> False
+- False -> True
 
-Some examples of `SkippedReasons`:
-- BackoffReason - "in backoff after failed scale-up"
-- MaxLimitReachedReason - "max node group size reached"
-- NotReadyReason - "not ready for scale-up"
+Pod stays with the conditions until the EOL. There is no point in clearing it, and it would be yet another kube api server call.
 
 
 ### Test Plan
@@ -528,16 +521,13 @@ well as the [existing list] of feature gates.
 -->
 
 - [x] Feature gate (also fill in values in `kep.yaml`)
-  - Feature gate name: `ScaleUpObservability` with values:
-    - `EventsOnly` -  current state,
-    - `EventsAndConditions` - produce both - we could turn it on scalability tests and assess the impact on the overall performance,
-    - `ConditionsOnly` - produce only new pod conditions.
+  - Feature gate name: `NodeProvisioningInProgressCondition`
   - Components depending on the feature gate: `cluster-autoscaler`.
 
 
 ###### Does enabling the feature change any default behavior?
 
-No, by default, CA will continue to use the `EventsOnly` for the scale up observability. 
+No. 
 
 ###### Can the feature be disabled once it has been enabled (i.e. can we roll back the enablement)?
 

From ac5288e03d723eb486ba8f6c1bbaed0c329c3048 Mon Sep 17 00:00:00 2001
From: Martyna Grotek <martynagrotek@google.com>
Date: Thu, 16 Oct 2025 15:28:23 +0000
Subject: [PATCH 3/3] Update target version and flag name

---
 keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml b/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml
index b7a5d39ca2f..1bd367c3ef4 100644
--- a/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml
+++ b/keps/sig-autoscaling/5616-ca-pod-condition/kep.yaml
@@ -24,18 +24,18 @@ stage: alpha
 # The most recent milestone for which work toward delivery of this KEP has been
 # done. This can be the current (upcoming) milestone, if it is being actively
 # worked on.
-latest-milestone: "v1.35"
+latest-milestone: "v1.36"
 
 # The milestone at which this feature was, or is targeted to be, at each stage.
 milestone:
-  alpha: "v1.35"
-  beta: "v1.36"
-  stable: "v1.37"
+  alpha: "v1.36"
+  beta: "v1.37"
+  stable: "v1.38"
 
 # The following PRR answers are required at alpha release
 # List the feature gate name and the components for which it must be enabled
 feature-gates:
-  - name: ScaleUpObservability
+  - name: NodeProvisioningInProgressCondition
     components:
       - cluster-autoscaler
 disable-supported: true