[AKS] `az aks nodepool update`, `az aks nodepool auto-scale`, `--enable-cluster-autoscaler`: Add CAS support for VMS agent pools by reneeli123 · Pull Request #33801 · Azure/azure-cli

reneeli123 · 2026-07-28T04:00:31Z

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Breaking Changes	Tests
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⚠️AzureCLI-BreakingChangeTest

⚠️acs

rule cmd_name rule_message suggest_message

⚠️ 1011 - SubgroupAdd aks nodepool auto-scale sub group aks nodepool auto-scale added

Related command

az aks create --vm-set-type VirtualMachines --node-vm-size --enable-cluster-autoscaler --min-count --max-count
az aks nodepool add --vm-set-type VirtualMachines --node-vm-size --enable-cluster-autoscaler --min-count --max-count
az aks nodepool update --enable-cluster-autoscaler --min-count --max-count
az aks nodepool update --disable-cluster-autoscaler
az aks nodepool update --update-cluster-autoscaler (now blocked for VirtualMachines pools; use auto-scale update)
az aks nodepool auto-scale add
az aks nodepool auto-scale update
az aks nodepool auto-scale delete

Description

This PR ports mixed-SKU cluster autoscaler (CAS) support for VirtualMachines (VMS) agent pools from aks-preview into azure-cli mainline ACS commands.

What is changed:

Add new command group:
- az aks nodepool auto-scale add
- az aks nodepool auto-scale update
- az aks nodepool auto-scale delete
Add parameter wiring and help for the new auto-scale commands.
Add VMS-specific autoscaler behavior in nodepool update:
- --enable-cluster-autoscaler converts all manual scale profiles to autoscale profiles using the same min/max values.
- --disable-cluster-autoscaler converts all autoscale profiles back to manual profiles, defaulting manual count from autoscale minCount.
- --update-cluster-autoscaler is rejected for VMS pools with a clear guidance message to use az aks nodepool auto-scale update.
Keep existing VMSS autoscaler behavior unchanged.
Add scenario and unit tests in ACS test suites to validate command behavior and conversion logic.

Effect:

Customers using VMS pools can now manage autoscale profiles directly (add/update/delete) and switch between manual and autoscale modes using supported commands.

Testing Guide

Example commands to validate behavior:

Create VMS cluster in autoscale mode

az aks create
--resource-group
--name
--vm-set-type VirtualMachines
--node-vm-size Standard_D4s_v3
--enable-cluster-autoscaler
--min-count 2
--max-count 5

Expected: agentPoolProfiles[0].virtualMachinesProfile.scale.autoscale is populated.

Add autoscaled VMS nodepool

az aks nodepool add
--resource-group
--cluster-name
--name
--vm-set-type VirtualMachines
--node-vm-size Standard_D4s_v3
--enable-cluster-autoscaler
--min-count 2
--max-count 5

Expected: nodepool virtualMachinesProfile.scale.autoscale[0] exists.

Manual -> auto conversion

az aks nodepool update
--resource-group
--cluster-name
--name
--enable-cluster-autoscaler
--min-count 2
--max-count 5

Expected: all manual profiles are converted into autoscale profiles.

Auto -> manual conversion

az aks nodepool update
--resource-group
--cluster-name
--name
--disable-cluster-autoscaler

Expected: autoscale profiles are converted to manual profiles; manual count defaults from minCount.

Manage individual autoscale profiles

az aks nodepool auto-scale add
--resource-group
--cluster-name
--name
--node-vm-size Standard_D2s_v3
--min-count 3
--max-count 5

az aks nodepool auto-scale update
--resource-group
--cluster-name
--name
--current-node-vm-size Standard_D2s_v3
--node-vm-size Standard_D8s_v3
--min-count 2
--max-count 4

az aks nodepool auto-scale delete
--resource-group
--cluster-name
--name
--current-node-vm-size Standard_D8s_v3

Expected: add/update/delete mutate virtualMachinesProfile.scale.autoscale as requested.

Guardrail behavior

az aks nodepool update
--resource-group
--cluster-name
--name
--update-cluster-autoscaler
--min-count 2
--max-count 5

Expected: validation failure for VMS pools directing to az aks nodepool auto-scale update.

Automated tests added/updated:

src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_aks_commands.py
src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_custom.py
src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_agentpool_decorator.py

History Notes

[AKS] az aks create, az aks nodepool add: Support --enable-cluster-autoscaler for VirtualMachines agent pools to create pools in autoscale mode
[AKS] az aks nodepool update: Support --enable-cluster-autoscaler for VirtualMachines agent pools by converting manual scale profiles to autoscale profiles
[AKS] az aks nodepool update: Support --disable-cluster-autoscaler for VirtualMachines agent pools by converting autoscale profiles back to manual profiles
[AKS] az aks nodepool update: Block --update-cluster-autoscaler for VirtualMachines agent pools and direct to az aks nodepool auto-scale update
[AKS] az aks nodepool auto-scale add: Add command to add an autoscale profile to a VirtualMachines agent pool
[AKS] az aks nodepool auto-scale update: Add command to update an autoscale profile of a VirtualMachines agent pool
[AKS] az aks nodepool auto-scale delete: Add command to delete an autoscale profile from a VirtualMachines agent pool

This checklist is used to make sure that common guidelines for a pull request are followed.

The PR title and description has followed the guideline in Submitting Pull Requests.
I adhere to the Command Guidelines.
I adhere to the Error Handling Guidelines.

azure-pipelines · 2026-07-28T04:00:39Z

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a0x1ab · 2026-07-28T04:01:50Z

/azp run

azure-pipelines · 2026-07-28T04:02:05Z

Azure Pipelines: Successfully started running 3 pipeline(s).

azure-pipelines · 2026-07-28T04:04:28Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

This PR brings mixed-SKU cluster autoscaler (CAS) support for VirtualMachines (VMS) agent pools into azure-cli mainline AKS commands, including a new az aks nodepool auto-scale command group and VMS-specific manual↔autoscale conversion behavior in aks nodepool update.

Changes:

Added az aks nodepool auto-scale add|update|delete commands for managing virtualMachinesProfile.scale.autoscale profiles on VMS pools.
Implemented VMS autoscaler conversion logic in the agentpool decorator for --enable-cluster-autoscaler / --disable-cluster-autoscaler, and blocked --update-cluster-autoscaler for VMS pools with guidance to use auto-scale update.
Added/updated unit and scenario tests covering the new commands and conversion behavior.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/azure-cli/azure/cli/command_modules/acs/custom.py	Adds the `aks_agentpool_auto_scale_*` custom command implementations for VMS autoscale profile CRUD.
src/azure-cli/azure/cli/command_modules/acs/commands.py	Registers the new `aks nodepool auto-scale` command group and its commands.
src/azure-cli/azure/cli/command_modules/acs/_params.py	Wires CLI parameters for the new `auto-scale` commands.
src/azure-cli/azure/cli/command_modules/acs/_help.py	Updates help text for autoscaler flags and documents the new `auto-scale` commands.
src/azure-cli/azure/cli/command_modules/acs/agentpool_decorator.py	Adds VMS-specific autoscaler validation/guardrails and manual↔autoscale conversion logic.
src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_custom.py	Adds unit tests for the new `aks_agentpool_auto_scale_*` functions.
src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_aks_commands.py	Adds scenario tests validating end-to-end behavior for VMS autoscale commands and conversions.
src/azure-cli/azure/cli/command_modules/acs/tests/latest/test_agentpool_decorator.py	Adds unit tests for VMS conversion and guardrail behavior in the decorator/context.

Comments suppressed due to low confidence (2)

src/azure-cli/azure/cli/command_modules/acs/custom.py:3710

aks_agentpool_auto_scale_update matches autoscale profiles with a case-sensitive a.size == current_node_vm_size comparison and does not validate the resulting min/max counts (or prevent renaming to a size that already exists). This can cause updates to fail unexpectedly (case mismatch) or create duplicate sizes/invalid min>max configurations.

    autoscale_exists = False
    for a in instance.virtual_machines_profile.scale.autoscale or []:
        if a.size == current_node_vm_size:
            autoscale_exists = True
            if node_vm_size is not None:

src/azure-cli/azure/cli/command_modules/acs/agentpool_decorator.py:1095

When enabling autoscaler on a VirtualMachines pool, vm_size can remain None if the pool has no manual profiles and the user doesn't pass --node-vm-size, which later leads to creating an autoscale profile with size=None. This should fail fast with a clear RequiredArgumentMissingError.

        # default vm_size for backward compatibility when no manual/autoscale profile exists
        if vm_size is None and manual_scale_profile:
            vm_size = manual_scale_profile[0].size

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…unts_in_autoscaler, correct help property path

a0x1ab · 2026-07-28T04:33:21Z

/azp run

azure-pipelines · 2026-07-28T04:33:38Z

Azure Pipelines: Successfully started running 3 pipeline(s).

FumingZhang

the PR title needs to be updated. Since this is a complicated change, you can include multiple lines of history notes by writing them in the corresponding section of the PR description.
there's also a need to commit the recording files to pass CI checks.

FumingZhang · 2026-07-28T04:40:03Z

@@ -15321,6 +15321,237 @@ def test_vms_agentpool_type(self, resource_group, resource_group_location):
            ],
        )

+    @AllowLargeResponse()
+    @AKSCustomResourceGroupPreparer(random_name_length=17, name_prefix="clitest", location="westus2")
+    def test_vms_cluster_create_and_add_autoscale_mode(self, resource_group, resource_group_location):


Queued live test to validate the change.

Got an error, fixing it now

Passed https://dev.azure.com/msazure/CloudNativeCompute/_build/results?buildId=174067548&view=results

a0x1ab · 2026-07-28T04:54:51Z

/azp run

azure-pipelines · 2026-07-28T04:55:08Z

Azure Pipelines: Successfully started running 3 pipeline(s).

a0x1ab · 2026-07-28T05:16:08Z

/azp run

azure-pipelines · 2026-07-28T05:16:25Z

Azure Pipelines: Successfully started running 3 pipeline(s).

a0x1ab · 2026-07-28T05:47:26Z

/azp run

azure-pipelines · 2026-07-28T05:47:43Z

Azure Pipelines: Successfully started running 3 pipeline(s).

a0x1ab · 2026-07-28T06:13:47Z

/azp run

azure-pipelines · 2026-07-28T06:14:03Z

Azure Pipelines: Successfully started running 3 pipeline(s).

a0x1ab · 2026-07-28T06:43:06Z

/azp run

azure-pipelines · 2026-07-28T06:43:23Z

Azure Pipelines: Successfully started running 3 pipeline(s).

Support CAS for VMS

ae3d8da

azure-client-tools-bot-prd Bot added this to the September 2026 (2026-09-01) milestone Jul 28, 2026

microsoft-github-policy-service Bot requested review from FumingZhang, elvazhu521, yanzhudd and yonzhan July 28, 2026 04:00

microsoft-github-policy-service Bot assigned yanzhudd Jul 28, 2026

microsoft-github-policy-service Bot added Auto-Assign Auto assign by bot AKS az aks/acs/openshift act-observability-squad labels Jul 28, 2026

reneeli123 marked this pull request as ready for review July 28, 2026 04:04

reneeli123 requested a review from a team as a code owner July 28, 2026 04:04

Copilot AI review requested due to automatic review settings July 28, 2026 04:04

Copilot started reviewing on behalf of reneeli123 July 28, 2026 04:04 View session

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Address Copilot review: fix return annotation, use self.__validate_co…

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…unts_in_autoscaler, correct help property path

FumingZhang reviewed Jul 28, 2026

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reneeli123 changed the title ~~[AKS] az aks --enable-cluster-autoscaler az aks nodepool auto-scale: Add CAS support for VMS agent pool commands~~ [AKS] az aks nodepool update, az aks nodepool auto-scale, --enable-cluster-autoscaler: Add CAS support for VMS agent pools Jul 28, 2026

Trigger CI

4e878f2

fix

6b83390

Align VMS mixed-SKU cluster autoscaler with aks-preview extension

f64e6b9

Fix live test

b08dbe1

Add recording for live test

6ea6fb1

FumingZhang approved these changes Jul 28, 2026

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