Trusted launch default and VMSS flex default conflict | az vmss create

[AjKundnani]

Describe the bug

Running command az vmss create generates below error as VMSS flex does not supports SystemAssigned identity. This could be due to implementation of Trusted launch as default and VMSS flex as default.

Command: az vmss create -n minvmss02 -g $rgName -l $loc
Error: "message":"Required parameter 'platformFaultDomainCount' is missing (null)."

Command: az vmss create --name vmssname --resource-group rgname --image imagealias --vm-sku vmsize
Error: [{"code":"InvalidParameter","target":"identity","message":"The value 'SystemAssigned' of parameter 'identity' is not allowed. Allowed values are: UserAssigned, None."}]}}

Related command

az vmss create

Errors

{"status":"Failed","error":{"code":"DeploymentFailed","target":"/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/cli1111rg/providers/Microsoft.Resources/deployments/vmss_deploy_ABoEgqebU41wMuCMFZTLjEEmovfylStS","message":"At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/arm-deployment-operations for usage details.","details":[{"code":"InvalidParameter","target":"platformFaultDomainCount","message":"Required parameter 'platformFaultDomainCount' is missing (null)."}]}}

{"status":"Failed","error":{"code":"DeploymentFailed","target":"/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/cli1111rg/providers/Microsoft.Resources/deployments/vmss_deploy_5VCbrHJ2JsnJMgYaeGFMg6xRPQ6KHoTO","message":"At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/arm-deployment-operations for usage details.","details":[{"code":"InvalidParameter","target":"identity","message":"The value 'SystemAssigned' of parameter 'identity' is not allowed. Allowed values are: UserAssigned, None."}]}}

Issue script & Debug output

Command: az vmss create -n minvmss02 -g $rgName -l $loc --vm-sku Standard_D2s_v3 --image Ubuntu2204 --debug****

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Expected behavior

VMSS flex is deployed with Gen2 OS image and Trusted launch security type.

Environment Summary

azure-cli 2.54.0

core 2.54.0
telemetry 1.1.0

Dependencies:
msal 1.24.0b2
azure-mgmt-resource 23.1.0b2

Python location 'C:\Program Files\Microsoft SDKs\Azure\CLI2\python.exe'
Extensions directory 'C:\Users\ajkundna.azure\cliextensions'

Python (Windows) 3.11.5 (tags/v3.11.5:cce6ba9, Aug 24 2023, 14:38:34) [MSC v.1936 64 bit (AMD64)]

Legal docs and information: aka.ms/AzureCliLegal

Unable to check if your CLI is up-to-date. Check your internet connection.

Additional context

No response

[yonzhan]

Thank you for opening this issue, we will look into it.

[yanzhudd]

Command: az vmss create -n minvmss02 -g $rgName -l $loc
Error: "message":"Required parameter 'platformFaultDomainCount' is missing (null)."

Command: az vmss create --name vmssname --resource-group rgname --image imagealias --vm-sku vmsize
Error: [{"code":"InvalidParameter","target":"identity","message":"The value 'SystemAssigned' of parameter 'identity' is not allowed. Allowed values are: UserAssigned, None."}]}}

Hi @Jing-song, let me confirm with you if this behavior meets expectation. Should this command be used with specifying --orchestration-mode to Uniform in these scenarios?

[Jing-song]

@yanzhudd @AjKundnani Yes, since the default value of --orchestration-mode has changed, we need to manually add --orchestration-mode Uniform to have the same behavior as before

Command: az vmss create -n minvmss02 -g $rgName -l $loc --vm-sku Standard_D2s_v3 --image Ubuntu2204

The previous behavior of this command was equivalent to adding --orchestration-mode Uniform by default.

[AjKundnani]

@yanzhudd @AjKundnani Yes, since the default value of --orchestration-mode has changed, we need to manually add --orchestration-mode Uniform to have the same behavior as before

Command: az vmss create -n minvmss02 -g $rgName -l $loc --vm-sku Standard_D2s_v3 --image Ubuntu2204

The previous behavior of this command was equivalent to adding --orchestration-mode Uniform by default.

@yanzhudd @Jing-song - Ideally end user should not specify additional parameters for default.
Request to debug cause of this conflict/error and add require fix to ensure SystemAssigned identity is not used.

TrustedLaunch VMs do not require SystemAssigned identity.

[Jing-song]

TrustedLaunch VMs do not require SystemAssigned identity.

@AjKundnani Flexible mode does not require SystemAssigned identity, does uniform mode still require it?

[yanzhudd]

Command: az vmss create --name vmssname --resource-group rgname --image imagealias --vm-sku vmsize
Error: [{"code":"InvalidParameter","target":"identity","message":"The value 'SystemAssigned' of parameter 'identity' is not allowed. Allowed values are: UserAssigned, None."}]}}

Hi @AjKundnani,
sorry I can't repro this error, could you please share the --image and --vm-sku you use?