Change password of Azure VM using PowerShell - azure

Question

I have tried this approach to change a password of an Azure VM:
$resgroup = "rsource1"
$vmName = "virtualmachine1"
$VM = Get-AzVM -ResourceGroupName $resgroup -Name $vmName
$Credential = Get-Credential
$VM | Set-AzureVMAccessExtension –UserName $Credential.UserName `
–Password $Credential.GetNetworkCredential().Password
$VM | Update-AzVM
But I keep getting this error:
Object reference not set to an instance of an object.
When I console.log the values of $Credential.UserName and $Credential.GetNetworkCredential().Password I got the values of username and password that I have inputted.
What am I missing here?

Answer 1

I've never used Set-AzureVMAccessExtension, but I've used the Az PowerShell equivalant Set-AzVMAccessExtension. It needs you to pass -Credential $Credential instead of -UserName and -Password.
You can try this script I made a while ago to to reset passwords for Azure VMs:
# Replace these values with your own
$resourceGroupName = "Servers-RG"
$vmName = "server1"
# Get the VM into an object
$vm = Get-AzVM -ResourceGroupName $resourceGroupName -Name $vmName
# Store credentials you want to change
$credential = Get-Credential -Message "Enter your username and password for $vmName"
# Store parameters in a hashtable for splatting
# Have a look at https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_splatting?view=powershell-7
$extensionParams = #{
'VMName' = $vmName
'Credential' = $credential
'ResourceGroupName' = $resourceGroupName
'Name' = 'AdminPasswordReset'
'Location' = $vm.Location
}
# Pass splatted parameters and update password
Set-AzVMAccessExtension #extensionParams
# Restart VM
# Don't need to pass any switches since they are inferred ByPropertyName
# Have a look at https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_pipelines?view=powershell-7
$vm | Restart-AzVM
I found that the password update doesn't happen until you restart the VM, so Restart-VM is required.

Answer 2

If anyone interested in the Linux (KISS) version (no VM restart needed):
$settings = '{}'
$protectedSettings = '{
"username": "<yourusername, prefer using Credentials object>",
"password": "<yourpassword, prefer using Credentials object>"
}'
Set-AzVMExtension `
-VMName $vmName `
-ResourceGroupName $rgName `
-Location $location `
-Name "VMAccessForLinux" `
-Publisher "Microsoft.OSTCExtensions" `
-ExtensionType "VMAccessForLinux" `
-TypeHandlerVersion "1.4" `
-Settingstring $settings `
-ProtectedSettingString $protectedSettings