Fallback to cached value if available by alt-dima · Pull Request #7317 · kedacore/keda

alt-dima · 2025-12-13T17:16:08Z

Adds new fallback behaviour "cached".
Fallback will return metric value from cache (if available)

Checklist

When introducing a new scaler, I agree with the scaling governance policy
I have verified that my change is according to the deprecations & breaking changes policy
Tests have been added
Ensure make generate-scalers-schema has been run to update any outdated generated files.
Changelog has been updated and is aligned with our changelog requirements
A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
A PR is opened to update the documentation on (repo) (if applicable)
Commits are signed with Developer Certificate of Origin (DCO - learn more)

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github-actions · 2025-12-13T17:16:16Z

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JorTurFer

I like this idea! just smal nits inline

JorTurFer · 2025-12-13T22:44:49Z

Could you open a PR also to docs repo adding the new option there too?

Signed-off-by: Dmitriy Altuhov <altuhovd@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Replace self-hosted ARM64 runners with GitHub's free ubuntu-24.04-arm runners. Consolidate ARM64 and AMD64 smoke tests into a unified matrix. Signed-off-by: Vincent Link <vlink@redhat.com> Co-authored-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> Signed-off-by: Dima Altukhov <dimaal@monday.com>

* Fix smoke tests To use `go.mod` version for restoring golang, checkout must happen before golang installation task Signed-off-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> * Remove duplicate checkout step in workflow Signed-off-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> * Apply suggestions from code review Signed-off-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> * Update pr-e2e.yml Signed-off-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> --------- Signed-off-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es> Signed-off-by: Dima Altukhov <dimaal@monday.com>

…dacore#7326) Bumps [github.com/expr-lang/expr](https://github.com/expr-lang/expr) from 1.17.6 to 1.17.7. - [Release notes](https://github.com/expr-lang/expr/releases) - [Commits](expr-lang/expr@v1.17.6...v1.17.7) --- updated-dependencies: - dependency-name: github.com/expr-lang/expr dependency-version: 1.17.7 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

* fix: projected service accounts are validated to prevent arbitrary path reads Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es> * validate signature Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es> --------- Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es> Signed-off-by: Dima Altukhov <dimaal@monday.com>

* Update releases Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz> * Update releases Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz> * fix linting issues Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz> --------- Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Signed-off-by: Rick Brouwer <rickbrouwer@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Signed-off-by: Shivamrut <incineroaraditya@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

…dacore#7351) Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 3.7.1 to 3.12.0. - [Release notes](https://github.com/docker/setup-buildx-action/releases) - [Commits](docker/setup-buildx-action@c47758b...8d2750c) --- updated-dependencies: - dependency-name: docker/setup-buildx-action dependency-version: 3.12.0 dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

…e#7352) Bumps [github/codeql-action](https://github.com/github/codeql-action) from 4.31.6 to 4.31.9. - [Release notes](https://github.com/github/codeql-action/releases) - [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md) - [Commits](github/codeql-action@fe4161a...5d4e8d1) --- updated-dependencies: - dependency-name: github/codeql-action dependency-version: 4.31.9 dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

…ore#7353) Bumps [oNaiPs/secrets-to-env-action](https://github.com/onaips/secrets-to-env-action) from 1.5 to 1.7. - [Release notes](https://github.com/onaips/secrets-to-env-action/releases) - [Commits](oNaiPs/secrets-to-env-action@ec46a22...be0f849) --- updated-dependencies: - dependency-name: oNaiPs/secrets-to-env-action dependency-version: '1.7' dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

the final semaphore acquisition was still missing, which resulted in loop not waiting until all metrics were gathered from each metrics API server Signed-off-by: julian GUINARD <julian.guinard@ovhcloud.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

* Include trigger actvivity in raw metrics Include information about trigger activity in raw metrics. This is usefull when a trigger defines `activityThreshold`, where non-zere value does not necessarily mean that the trigger is active. Signed-off-by: Josef Karasek <karasek.jose@gmail.com> * update changelog Signed-off-by: Josef Karasek <karasek.jose@gmail.com> * Fix lint Signed-off-by: Josef Karasek <karasek.jose@gmail.com> --------- Signed-off-by: Josef Karasek <karasek.jose@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Signed-off-by: Dima Altukhov <dimaal@monday.com>

JorTurFer · 2026-01-09T11:03:20Z

@kedacore/keda-core-contributors

alt-dima · 2026-01-09T11:50:03Z

Interesting, I just noticed this information. And a bit confused.
So this PR is irrelevant. But I was sure until this time that HPA stops scaling at all (nor UP nor DOWN)

If multiple metrics are specified in a HorizontalPodAutoscaler, this calculation is done for each metric, and then the largest of the desired replica counts is chosen. If any of these metrics cannot be converted into a desired replica count (e.g. due to an error fetching the metrics from the metrics APIs) and a scale down is suggested by the metrics which can be fetched, scaling is skipped. This means that the HPA is still capable of scaling up if one or more metrics give a desiredReplicas greater than the current value.

https://kubernetes.io/docs/concepts/workloads/autoscaling/horizontal-pod-autoscale/#algorithm-details

alt-dima · 2026-01-09T12:19:47Z

kedacore/keda-docs#1686
kedacore/charts#804

JorTurFer

Looking nice! just a question inlined 😄

JorTurFer · 2026-01-12T20:37:32Z

+// scaler instances but keep last known good metrics available for fallback behavior.
+func (h *scaleHandler) resetScalersCacheKeepMetrics(ctx context.Context, scalableObject interface{}) error {


Does it make sense to rename the current to something like DeleteScalersCache and the new one as ResetScalersCache? I understand that this new one is called during refresh and the previous one during scaledobject update/delete

@kedacore/keda-core-contributors @kedacore/keda-core-maintainers ?

github-actions · 2026-03-25T03:11:16Z

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

github-actions · 2026-04-01T03:13:20Z

This pull request has been automatically closed due to inactivity.

alt-dima requested a review from a team as a code owner December 13, 2025 17:16

keda-automation requested a review from a team December 13, 2025 17:16

JorTurFer reviewed Dec 13, 2025

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Comment thread pkg/fallback/fallback.go Outdated

Comment thread pkg/scaling/cache/metricscache/metrics_record_test.go Outdated

keda-automation requested a review from a team December 14, 2025 08:41

rickbrouwer added the docs:pending All issues where docs are pending addition/update label Dec 17, 2025

alt-dima and others added 15 commits January 9, 2026 12:52

copy code back

15d11ae

Signed-off-by: Dmitriy Altuhov <altuhovd@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

chore: smoke e2e tests on PR (kedacore#7319)

a05736c

Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es> Signed-off-by: Dima Altukhov <dimaal@monday.com>

fix: Update Kubernetes cluster naming in CI workflow (kedacore#7342)

1c65569

Signed-off-by: Rick Brouwer <rickbrouwer@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

Docs: update ROADMAP (kedacore#7328)

e083f0c

Signed-off-by: Shivamrut <incineroaraditya@gmail.com> Signed-off-by: Dima Altukhov <dimaal@monday.com>

fixes

51bd50c

Signed-off-by: Dima Altukhov <dimaal@monday.com>

alt-dima force-pushed the feature/dimaal/fallback-to-cached branch from 597d1d6 to 51bd50c Compare January 9, 2026 10:52

Merge branch 'main' into feature/dimaal/fallback-to-cached

3eefac1

This was referenced Jan 9, 2026

Add cached behavior to CRD kedacore/charts#804

Open

add cached behavior to docs kedacore/keda-docs#1686

Closed

JorTurFer reviewed Jan 9, 2026

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Comment thread pkg/scaling/cache/metricscache/metrics_record.go

JorTurFer reviewed Jan 12, 2026

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rickbrouwer added waiting-author-response All PR's or Issues where we are waiting for a response from the author and removed docs:pending All issues where docs are pending addition/update labels Jan 23, 2026

github-actions Bot added the stale All issues that are marked as stale due to inactivity label Mar 25, 2026

github-actions Bot closed this Apr 1, 2026

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Fallback to cached value if available#7317

Fallback to cached value if available#7317
alt-dima wants to merge 16 commits intokedacore:mainfrom
alt-dima:feature/dimaal/fallback-to-cached

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		// scaler instances but keep last known good metrics available for fallback behavior.
		func (h *scaleHandler) resetScalersCacheKeepMetrics(ctx context.Context, scalableObject interface{}) error {

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