✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity #5711

LiangquanLi930 · 2025-10-15T18:37:11Z

✨ Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity and NodeInfo

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR implements the Cluster API autoscaling from zero proposal for CAPA by adding a controller that automatically populates AWSMachineTemplate.Status.Capacity with instance type information.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Checklist:

Release note:

Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity

k8s-ci-robot · 2025-10-15T18:37:18Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign richardcase for approval. For more information see the Code Review Process.

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

Needs approval from an approver in each of these files:

OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

k8s-ci-robot · 2025-10-15T18:37:20Z

Hi @LiangquanLi930. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

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-sigs/prow repository.

elmiko · 2025-10-15T18:47:47Z

/ok-to-test

… capacity

LiangquanLi930 · 2025-11-03T15:25:17Z

/test pull-cluster-api-provider-aws-e2e

k8s-ci-robot · 2025-11-03T16:43:34Z

@LiangquanLi930: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-provider-aws-e2e	`3bf0acb`	link	false	`/test pull-cluster-api-provider-aws-e2e`

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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-sigs/prow repository. I understand the commands that are listed here.

LiangquanLi930 · 2025-11-04T08:02:01Z

@elmiko @nrb @chrischdi Thanks for your review! When you have time, could you help to review again? Thanks!

LiangquanLi930 · 2025-11-04T08:05:35Z

controllers/awsmachinetemplate_controller.go

+	if info.MemoryInfo != nil && info.MemoryInfo.SizeInMiB != nil {
+		memoryBytes := *info.MemoryInfo.SizeInMiB * 1024 * 1024
+		resourceList[corev1.ResourceMemory] = *resource.NewQuantity(memoryBytes, resource.BinarySI)
+	}


I'm not sure whether my handling of this part is correct, and I’m also uncertain about which unit I should be using.

the machine-api annotations used a calculation of MiB for its value. for the cluster-api implementation we should simply be using a Quantity for this value, no need to convert to MiB.

you can see an example in the cluster-api autoscaler docs.

i /think/ the logic you have here is correct though, but i don't think we need to do the conversion. unless we need it for the Quantity.

chrischdi · 2025-11-04T11:10:20Z

controllers/awsmachinetemplate_controller.go

+	// Skip if capacity and nodeInfo are already set
+	if len(awsMachineTemplate.Status.Capacity) > 0 && awsMachineTemplate.Status.NodeInfo != nil {
+		return ctrl.Result{}, nil
+	}
+


Suggested change

// Skip if capacity and nodeInfo are already set

if len(awsMachineTemplate.Status.Capacity) > 0 && awsMachineTemplate.Status.NodeInfo != nil {

return ctrl.Result{}, nil

}

Either drop the skip, or do not skip if template.Spec.Template.Spec.AMI.ID is empty.

elmiko

i think this is looking good, although i'm not sure we need to do the conversion for the memory value.

elmiko · 2025-11-05T20:19:21Z

controllers/awsmachinetemplate_controller.go

+	if info.MemoryInfo != nil && info.MemoryInfo.SizeInMiB != nil {
+		memoryBytes := *info.MemoryInfo.SizeInMiB * 1024 * 1024
+		resourceList[corev1.ResourceMemory] = *resource.NewQuantity(memoryBytes, resource.BinarySI)
+	}


the machine-api annotations used a calculation of MiB for its value. for the cluster-api implementation we should simply be using a Quantity for this value, no need to convert to MiB.

you can see an example in the cluster-api autoscaler docs.

i /think/ the logic you have here is correct though, but i don't think we need to do the conversion. unless we need it for the Quantity.

k8s-ci-robot added kind/feature Categorizes issue or PR as related to a new feature. do-not-merge/release-note-label-needed Indicates that a PR should not merge because it's missing one of the release note labels. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Oct 15, 2025

k8s-ci-robot added the needs-priority label Oct 15, 2025

k8s-ci-robot requested review from AndiDog and cnmcavoy October 15, 2025 18:37

k8s-ci-robot added needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Oct 15, 2025

LiangquanLi930 changed the title ~~✨ Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity~~ WIP ✨ Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity Oct 15, 2025

k8s-ci-robot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Oct 15, 2025

k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Oct 15, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 7 times, most recently from f1ee365 to 3be8f4d Compare October 20, 2025 11:21

k8s-ci-robot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Oct 20, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 2 times, most recently from 01be987 to 915f55b Compare October 20, 2025 12:57

k8s-ci-robot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Oct 20, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch from 915f55b to b3850d1 Compare October 20, 2025 14:42

k8s-ci-robot removed the size/L Denotes a PR that changes 100-499 lines, ignoring generated files. label Oct 20, 2025

k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 30, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 3 times, most recently from b0eae44 to 6ab7428 Compare October 31, 2025 06:06

k8s-ci-robot added do-not-merge/contains-merge-commits and removed needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. labels Oct 31, 2025

Implement autoscaling from zero by auto-populating AWSMachineTemplate…

9a92a43

… capacity

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch from 6df5996 to 5b5a139 Compare October 31, 2025 07:26

k8s-ci-robot removed the do-not-merge/contains-merge-commits label Oct 31, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 2 times, most recently from af3844f to 8371031 Compare November 3, 2025 08:43

LiangquanLi930 changed the title ~~✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity~~ WIP ✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity Nov 3, 2025

k8s-ci-robot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Nov 3, 2025

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 2 times, most recently from 56615b5 to 3bf0acb Compare November 3, 2025 13:23

add AWSMachineTemplate NodeInfo

86fe072

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch 3 times, most recently from ca67a57 to 2090092 Compare November 4, 2025 06:45

LiangquanLi930 changed the title ~~WIP ✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity~~ WIP ✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate Capacity and NodeInfo Nov 4, 2025

LiangquanLi930 changed the title ~~WIP ✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate Capacity and NodeInfo~~ ✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity Nov 4, 2025

k8s-ci-robot removed the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Nov 4, 2025

LiangquanLi930 commented Nov 4, 2025

View reviewed changes

chrischdi reviewed Nov 4, 2025

View reviewed changes

Fix review comments

b0477c1

LiangquanLi930 force-pushed the opt-in-autoscaling-from-zero branch from 2090092 to b0477c1 Compare November 4, 2025 14:17

elmiko reviewed Nov 5, 2025

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity #5711

✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity #5711

LiangquanLi930 commented Oct 15, 2025 •

edited

Loading

Uh oh!

k8s-ci-robot commented Oct 15, 2025

Uh oh!

k8s-ci-robot commented Oct 15, 2025

Uh oh!

elmiko commented Oct 15, 2025

Uh oh!

LiangquanLi930 commented Nov 3, 2025

Uh oh!

k8s-ci-robot commented Nov 3, 2025

Uh oh!

LiangquanLi930 commented Nov 4, 2025

Uh oh!

LiangquanLi930 Nov 4, 2025

Uh oh!

elmiko Nov 5, 2025

Uh oh!

chrischdi Nov 4, 2025

Uh oh!

LiangquanLi930 Nov 4, 2025

Uh oh!

elmiko left a comment

Uh oh!

elmiko Nov 5, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity #5711

Are you sure you want to change the base?

✨ feat: Implement autoscaling from zero by auto-populating AWSMachineTemplate capacity #5711

Conversation

LiangquanLi930 commented Oct 15, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

k8s-ci-robot commented Oct 15, 2025

Uh oh!

k8s-ci-robot commented Oct 15, 2025

Uh oh!

elmiko commented Oct 15, 2025

Uh oh!

LiangquanLi930 commented Nov 3, 2025

Uh oh!

k8s-ci-robot commented Nov 3, 2025

Uh oh!

LiangquanLi930 commented Nov 4, 2025

Uh oh!

LiangquanLi930 Nov 4, 2025

Choose a reason for hiding this comment

Uh oh!

elmiko Nov 5, 2025

Choose a reason for hiding this comment

Uh oh!

chrischdi Nov 4, 2025

Choose a reason for hiding this comment

Uh oh!

LiangquanLi930 Nov 4, 2025

Choose a reason for hiding this comment

Uh oh!

elmiko left a comment

Choose a reason for hiding this comment

Uh oh!

elmiko Nov 5, 2025

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

LiangquanLi930 commented Oct 15, 2025 •

edited

Loading