[AKS] az aks nodepool: Add --use-patch-api for vms agentpool scale

[Shaoru Hu (HuShaoRu)]

🤖 PR Validation — ⚠️ Review suggested

Breaking Changes
⚠️ None

⚠️Azure CLI Extensions Breaking Change Test

⚠️aks-preview

rule	cmd_name	rule_message	suggest_message
⚠️ 1006 - ParaAdd	aks nodepool manual-scale add	cmd aks nodepool manual-scale add added parameter use_patch_api
⚠️ 1006 - ParaAdd	aks nodepool manual-scale delete	cmd aks nodepool manual-scale delete added parameter use_patch_api
⚠️ 1006 - ParaAdd	aks nodepool manual-scale update	cmd aks nodepool manual-scale update added parameter use_patch_api

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Related command

az aks nodepool scale --use-patch-api
az aks nodepool manual-scale --use-patch-api

add a new bool parameter --use-patch-api, so vms pool scale can use patch api instead of put api. (this parameter is already supported for vmss pool)

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Thank you for your contribution Shaoru Hu (@HuShaoRu)! We will review the pull request and get back to you soon.

[Copilot]

🟡 Changes recommended

PATCH routing and help text unintentionally include untested AvailabilitySet and FlexNodes pools.

2 open findings

• Limit PATCH behavior to VMSS and VirtualMachines pools · New
• Document PATCH support only for supported pool types · New

What changed in this PR

Extends PATCH-based AKS node-pool scaling to VirtualMachines pools and manual-scale operations.

Changes:

• Adds --use-patch-api to manual-scale commands.
• Builds VirtualMachines PATCH payloads.
• Adds integration tests and recordings.

File	Description
HISTORY.rst	Documents PATCH support.
test_aks_commands.py	Tests VMSS and VirtualMachines scaling.
test_aks_nodepool_scale_vmss_with_patch_api.yaml	Records VMSS PATCH behavior.
custom.py	Implements PATCH payloads and routing.
_params.py	Registers and documents the option.

🧠 Review effort: Balanced

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[Yong Zhang (yonzhan)]

/azp run

[azure-pipelines]

Azure Pipelines:
Successfully started running 2 pipeline(s).

[x-engineering-agent]

X Engineering Agent Report

Review — Comments

Shaoru Hu (@HuShaoRu)

Review

The completed upstream CI snapshot has no failures. One scope regression remains in PATCH routing; the default PUT path should stay unchanged for pool types outside this feature.

Scope-consistency finding

PR-related: src/aks-preview/azext_aks_preview/custom.py:2503 changes the VMSS-only guard to if use_patch_api. This now routes AvailabilitySet and FlexNodes pools through _aks_agentpool_scale_patch, whose non-VirtualMachines branch sends a count-only PATCH. Previously those types retained begin_create_or_update even with the flag. The description and added scenarios establish VMSS/VirtualMachines support, not this additional behavior change. This confirms Copilot discussion 4263658830; the broadened help at _params.py:2839 has the same scope problem (4263658905).

Restrict PATCH dispatch to CONST_VIRTUAL_MACHINE_SCALE_SETS and CONST_VIRTUAL_MACHINES, preserve the prior PUT fallback for other types, and name those supported types in the flag help. Verify both supported types call begin_update, while AvailabilitySet/FlexNodes retain the prior PUT path with the flag enabled. Rerun the three focused scenarios below after the routing correction.

Test validation

• Agent live test: Not run; this is a review-only PR. Check author-provided test evidence and upstream CI separately.
• Regression coverage: Not applicable to the changed files.

The changed src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py scenarios cover VMSS scaling, VirtualMachines scale up/down, and adding/updating/deleting a second manual profile. Matching recordings are included at tests/latest/recordings/test_aks_nodepool_scale_vmss_with_patch_api.yaml, test_aks_nodepool_scale_vms_with_patch_api.yaml, and test_aks_nodepool_manual_scale_update_with_patch_api.yaml beneath that extension. These are author-provided artifacts, not Agent live-test results. The automatic coverage result above does not verify extension scenario coverage; the newly expanded AvailabilitySet/FlexNodes dispatch has no focused assertion. Validate the routing guard with mocked PUT/PATCH calls and rerun test_aks_nodepool_scale_vmss_with_patch_api, test_aks_nodepool_scale_vms_with_patch_api, and test_aks_nodepool_manual_scale_update_with_patch_api in the extension's scenario file.

Risk assessment

31/100 · Medium · High confidence

The Medium rating is driven by public CLI behavior.

• Change scope: 7 changed files, 4880 changed lines (+4869 / -11), including 2 production files.
• Affected components: aks-preview
• Risk drivers: public CLI behavior (+18)
• Regression evidence: Changed regression tests are included, reducing risk.
• Confidence: High because changed-line patches were available for every production file.
• Required review: Owning-squad review is recommended for aks-preview before merge.

Posted by x-engineering-agent (Reviewer)