add osdisk full cache feature

[weiliu2dev]

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[azure-client-tools-bot-prd]

❌Azure CLI Extensions Breaking Change Test

❌aks-preview

rule	cmd_name	rule_message	suggest_message
❌ 1010 - ParaPropUpdate	aks nodepool add	cmd aks nodepool add update parameter spot_max_price: updated property default from nan to nan	please change property default from nan to nan for parameter spot_max_price of cmd aks nodepool add
⚠️ 1006 - ParaAdd	aks create	cmd aks create added parameter enable_os_disk_full_caching
⚠️ 1006 - ParaAdd	aks nodepool add	cmd aks nodepool add added parameter enable_os_disk_full_caching

[azure-client-tools-bot-prd]

Hi @weiliu2dev,
Please write the description of changes which can be perceived by customers into HISTORY.rst.
If you want to release a new extension version, please update the version in setup.py as well.

[yonzhan]

Thank you for your contribution! We will review the pull request and get back to you soon.

[github-actions]

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[github-actions]

Hi @weiliu2dev

Release Suggestions

Module: aks-preview

• Update VERSION to 21.0.0b2 in src/aks-preview/setup.py

Notes

• For more info about extension versioning, please refer to Extension version schema

[Copilot]

Pull request overview

Adds support in aks-preview for enabling the full-cache ephemeral OS disk feature on AKS node pools via a new preview flag, including argument plumbing, validation, help text, and test coverage updates.

Changes:

• Introduces --enable-os-disk-full-caching (preview) for az aks create and az aks nodepool add, wiring it into the agentpool decorator to set enable_os_disk_full_caching.
• Adds CLI-side validation to reject the flag when --node-osdisk-type Managed is specified.
• Updates help/history and adds unit + live-only scenario tests for the new behavior.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/aks-preview/HISTORY.rst	Documents the new preview flag and its prerequisites/immutability notes.
src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py	Adds live-only end-to-end scenarios for create/nodepool add using the new flag.
src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py	Adds unit tests for context getter + decorator setup logic for the new property.
src/aks-preview/azext_aks_preview/custom.py	Adds the new argument to aks_create and aks_agentpool_add function signatures so it flows via raw_parameters.
src/aks-preview/azext_aks_preview/agentpool_decorator.py	Implements getter + setup method to apply enable_os_disk_full_caching onto the AgentPool model.
src/aks-preview/azext_aks_preview/_validators.py	Adds validation preventing use with Managed OS disks.
src/aks-preview/azext_aks_preview/_params.py	Registers the new CLI arguments for create/nodepool add and wires the validator.
src/aks-preview/azext_aks_preview/_help.py	Documents the new flag in command help for create/nodepool add.

Comments suppressed due to low confidence (1)

src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py:7282

• This command also uses --enable-osdisk-full-caching, but _params.py only registers --enable-os-disk-full-caching and --enable-osdisk-fc. The live-only test will fail unless the option name is corrected (or an alias is added).

            "aks nodepool add --resource-group={resource_group} --cluster-name={name} --name={nodepool2_name} "
            "--node-vm-size Standard_D8ds_v5 --node-osdisk-type Ephemeral "
            "--enable-osdisk-full-caching "
            "--aks-custom-headers=AKSHTTPCustomFeatures=Microsoft.ContainerService/FullCachePreview",
            checks=[

[FumingZhang]

Please fix this error

• FAIL - HIGH severity: missing_parameter_help
  Parameter: aks create, enable_os_disk_full_caching - Missing help
  Parameter: aks nodepool add, enable_os_disk_full_caching - Missing help

https://github.com/Azure/azure-cli-extensions/actions/runs/25900023873/job/76121212994?pr=9875

[yanzhudd]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[FumingZhang]

lgtm

[weiliu2dev]