Add config knob MaxScale for setting default "autoscaling.knative.dev/maxScale"

[arturenault]

/lint
Fixes #8627

Proposed Changes

• Add config knob for max-scale to allow for cluster-wide setting of default max-scale for revisions where "autoscaling.knative.dev/maxScale" isn't specified

Release Note

Add config knob "max-value," which allows for setting a cluster-wide value for the max scale of any revision that doesn't have the "autoscaling.knative.dev/maxScale" annotation. The default of 0 conforms to previous behavior: revisions created with no annotation can scale without an upper bound.

[knative-prow-robot]

@arturenault: 0 warnings.

In response to this:

/lint
Fixes #8627

Proposed Changes

• Add config knob for default-max-scale to allow for cluster-wide setting of default-max-scale

Release Note

Add config knob "default-max-value," which allows for setting a cluster-wide value for the max scale of a revision after creation. The config applies to any revision which doesn't have the "autoscaling.knative.dev/maxScale" annotation. The default of 0 conforms to previous behavior: revisions created with no annotation can scale without an upper bound.

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.

[yanweiguo]

/lgtm

[julz]

mostly lgtm, couple more nits

[lgtm-com]

This pull request introduces 1 alert when merging 2cbce5f into cdf76a9 - view on LGTM.com

new alerts:

• 1 for Useless assignment to local variable

[julz]

looks like the tests are still failing. I think because you've checked in generate-groups.sh and generate-knative.sh with a permission change and removed zz_generated.deepcopy.go. If you re-run ./hack/update-codegen.sh and make sure everything works locally afterwards with go test ./... that should fix it.

[knative-metrics-robot]

The following is the coverage report on the affected files.
Say /test pull-knative-serving-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/autoscaling/kpa/kpa.go	94.8%	94.9%	0.1
pkg/reconciler/autoscaling/kpa/scaler.go	93.4%	94.3%	0.9

[julz]

lgtm! thanks for the contribution @arturenault

/lgtm
/approve
/assign @vagababov

[vagababov]

/lgtm
/approve
Thanks.

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: arturenault, julz, vagababov

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

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Needs approval from an approver in each of these files:

• config/OWNERS [vagababov]
• pkg/apis/autoscaling/OWNERS [julz,vagababov]
• pkg/autoscaler/OWNERS [julz,vagababov]
• pkg/reconciler/autoscaling/OWNERS [julz,vagababov]

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[julz]

/retest

[julz]

looks like #8953.

/retest

[knative-test-reporter-robot]

The following jobs failed:

Test name	Triggers	Retries
pull-knative-serving-integration-tests		0/3

Failed non-flaky tests preventing automatic retry of pull-knative-serving-integration-tests:

test/conformance/api/v1.TestContainerExitingMsg
test/conformance/api/v1alpha1.TestContainerExitingMsg
test/conformance/api/v1beta1.TestContainerExitingMsg

[arturenault]

/retest

[markusthoemmes]

@arturenault thanks for this! Would you please send a PR against the docs repository too to add this new global default? I'd imagine it to go here https://github.com/knative/docs/blob/master/docs/serving/autoscaling/scale-bounds.md#upper-bound and add a global key to the upper bound description, including an example for the ConfigMap/Operator in the example section of the upper-bound.

Lemme know if you need help there.