REST API request returns "BadRequest" for VMSS

Jaewoo Kim 20

Working on REST API to retrieve instances from VMSS.

https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-orchestration-modes#list-scale-sets-vm-api-changes

found that based on orchestration mode:

'flexible' : use standard VM API

'uniform' : use VMSS API

So, 'flexible' VMSS seems fine. But, still got error from a VMSS resource with 'Uniform'

Microsoft.Compute/virtualMachineScaleSets/{UniformVMSS}/virtualMachines?api-version=2019-12-01&$expand=instanceView

{

    "error": {

        "code": "BadRequest",

        "message": "Operation 'VirtualMachineScaleSets.virtualMachines.GET' is not allowed on Virtual Machine Scale Set {UniformVMSS}."

    }

}

Is there any case that we cannnot retireve VMs from VMSS('uniform') using the REST call above?

How can I determine which API to use?

1 answer

shiva patpi 13,256 Reputation points Microsoft Employee

2023-11-07T06:54:25.9566667+00:00
@Jaewoo Kim

As per the document: https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-orchestration-modes?WT.mc_id=modinfra-31635-pierrer#what-has-changed-with-flexible-orchestration-mode

For uniform, it works with the normal VMSS REST APIs:

If you try to use the same VMSS REST APIs for Flexible , it won't work:

{ "error": { "code": "BadRequest", "message": "Operation 'VirtualMachineScaleSets.virtualMachines.GET' is not allowed on Virtual Machine Scale Set 'testvmssflixible'." } }

So while querying Flexible VMSS we can use the normal VM REST API to query individual VMs

Kindly let us know if you have additional questions !

Regards,

Shiva.
Please sign in to rate this answer.
Jaewoo Kim 20 Reputation points

2023-11-07T14:40:30.6733333+00:00

Hi! Shiva.

Thank you for your quick response.

But, the explanation you provided was the same as what I expected.

Could you give one more look for the original question?

The problematic resource works just like 'Flexible' even though it is 'Uniform'.

I wonder why... and if there is a case for this?

shiva patpi 13,256 Reputation points Microsoft Employee

2023-11-07T16:41:22.19+00:00

@Jaewoo Kim

So for your scenario, it seems the VMSS REST API is not working for the Uniform but it is working for the Flex?

Regards,

Shiva.

Jaewoo Kim 20 Reputation points

2023-11-07T16:58:20.54+00:00

'Flex' works as intended(as you described). 'Uniform' also worked in some VMSS resources, but encountered one exception so far.

For example, I have three VMSS.

one vmss with flex -> using VM REST API works fine.

one vmss with uniform -> using VMSS REST API works fine.

one vmss with uniform -> using VMSS REST does not work. using VM REST worked. <- this is an issue.

Jaewoo Kim 20 Reputation points

2023-11-07T17:01:22.44+00:00

Deleted the duplicated comment

shiva patpi 13,256 Reputation points Microsoft Employee

2023-11-08T19:40:55.48+00:00

@Jaewoo Kim , That's interesting , If it is happening only for 1 Uniform VMSS , then you might have to check the whole configuration for that VMSS and compare with the other Uniform VMSS.

Jaewoo Kim 20 Reputation points

2023-11-08T20:56:45.7066667+00:00

Compared to the other two VMSS (Response from VMSS API)

List VMSS using call: Microsoft.Compute/virtualMachineScaleSets?api-version=2019-12-01

got 3 resources( all uniform)

two VMSS: contains name, id, type, location, tags, identity, sku, properties

problematic VMSS: contains name, id, type, location, properties

only the problematic VMSS contains singlePlacementGroup as true, does it affect?

Isn't there any thing we consider other than orchestrationMode?

Isn't there any similar case reported?

shiva patpi 13,256 Reputation points Microsoft Employee

2023-11-14T06:53:11.54+00:00

Jaewoo Kim - I was looking around & don't see any similar issues reported on this!

Do you have any other VMSS with Uniform + SinglePlacementGroup as true ?

Regards,

Shiva.

Jaewoo Kim 20 Reputation points

2023-11-15T16:37:52.5733333+00:00

Hi! Shiva.

Thank you for keeping following up this.

No, the account has 3 vmsses and the one is only one.

Then, another question.

In which case does vmss api return only this information for "Get providers/Microsoft.Compute/virtualMachineScaleSets/{VMSS name}" command?

I could not create VMSS like this through console. ex. without networking..

{ "name": "{name}", "id": "/subscriptions/{......}", "type": "Microsoft.Compute/virtualMachineScaleSets", "location": "southcentralus", "properties": { "singlePlacementGroup": true, "orchestrationMode": "Uniform", "provisioningState": "Succeeded", "uniqueId": "{id}", "platformFaultDomainCount": 2 } }

shiva patpi 13,256 Reputation points Microsoft Employee

2023-11-22T17:03:00.56+00:00

@Jaewoo Kim ,

I am not finding any scenarios - I kept trying to repro your issue with different configuration options in the VMSS - but still not able to repro it !!

I didn't get your latest question: "In which case does vmss api return only this information for "Get providers/Microsoft.Compute/virtualMachineScaleSets/{VMSS name}" command?"

Can you kindly expand a little bit !

Regards,

Shiva.

Jaewoo Kim 20 Reputation points

2023-11-22T21:19:28.0033333+00:00

Hi! Shiva!

The last question was.. the example output is the actual whole response comes from the Get API call mentioned. It seems having not enough information in it, compared to other the same kind resources. I thought that might be a clue.

For example, when I tried to spin up one VMSS through Azure console(GUI), another resource shows like this.

{ "name": "{name}", "id": "/subscriptions/{...}", "type": "Microsoft.Compute/virtualMachineScaleSets", "location": "eastus", "sku": { "name": "Standard_DS1_v2", "tier": "Standard", "capacity": 2 }, "properties": { "singlePlacementGroup": false, "orchestrationMode": "Uniform", "upgradePolicy": { "mode": "Manual" }, "scaleInPolicy": { "rules": [ "Default" ] }, "virtualMachineProfile": { "osProfile": {...}, "storageProfile": {...}, "diagnosticsProfile": { "bootDiagnostics": { "enabled": true } }, "extensionProfile": { "extensions": [] } }, "provisioningState": "Succeeded", "overprovision": false, "doNotRunExtensionsOnOverprovisionedVMs": false, "uniqueId": "...", "platformFaultDomainCount": 1 } }

shiva patpi 13,256 Reputation points Microsoft Employee

2023-12-06T23:01:57.5733333+00:00

Jaewoo Kim - That seems to be strange! VMSS should have all the information more significantly the block "VirtualMachineProfile" should always be there...
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Share via

REST API request returns "BadRequest" for VMSS

1 answer

Your answer