Set-AzVMOperatingSystem won't work for existing VMs

[KMoraz]

Description

This might be a documentation error, as official docs doesn't explicitly specify that Set-AzVMOperatingSystem cmdlet intended for new VMs and won't work for existing ones. The examples also target new VMs.

Issue script & Debug output

$vm = Get-AzVM -ResourceGroupName "someRG" -VMName "someVM"

# Running VM has DisablePasswordAuthentication=false, try to revert that:
Set-AzVMOperatingSystem -VM $vm -Linux -ComputerName $vm.OSProfile.ComputerName -Credential $cred -DisablePasswordAuthentication

# Refresh current configuration
(Get-AzVM -ResourceGroupName $vm.ResourceGroupName -VMName $vm.Name).OSProfile.LinuxConfiguration.DisablePasswordAuthentication

# output: False

Environment data

Name                           Value
----                           -----
PSVersion                      7.2.1
PSEdition                      Core
GitCommitId                    7.2.1
OS                             Microsoft Windows 10.0.22523
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Module versions

Name         Version
----         -------
Az.Accounts  2.2.3
Az.Compute   4.8.0
Az.Resources 3.1.1

Error output

No response

[dingmeng-xue]

Thanks for reporting. We believe this inconsistency should be resolve by service side. I reply team member to look into it further.

[SaurabhSharma-MSFT]

@KMoraz Thanks for your feedback. You are correct, and the cmdlet Set-AzVMOperatingSystem is not working to update linux properties. I am working internally on the same and update the documentation as required.

[SaurabhSharma-MSFT]

@KMoraz I have got the confirmation and this command is intended to be used on local VM objects to update OS properties before VM creation. This is by design and we cannot modify OS properties after the creation of the VM using this command.

[KMoraz]

@SaurabhSharma-MSFT I assumed that was the case, which is why I indicated that it was probably a documentation error.

Subtitle should be: Sets operating system properties during creation of a new virtual machine.

[SaurabhSharma-MSFT]

@KMoraz Thanks for your suggestions. I have submitted PR to update the documentation and it will be merged once approved by the reviewers.
We will now proceed to close this thread. If there are further questions regarding this matter, please reopen it and we will gladly continue the discussion.