#https://learn.microsoft.com/en-us/azure/virtual-machines/windows-in-place-upgrade
# Customer specific parameters
# Resource group of the source VM
$resourceGroup = "YOURRESOURCEGROUPNAMEHERE"

# Location of the source VM
$location = "YOURLOCATIONHERE"

# Zone of the source VM, if any
$zone = ""

# Disk name for the that will be created
$diskName = "WindowsServer2025UpgradeDisk"

# Target version for the upgrade - must be either server2022Upgrade, server2019Upgrade, server2016Upgrade or server2012Upgrade
$sku = "server2025Upgrade"

# Common parameters

$publisher = "MicrosoftWindowsServer"
$offer = "WindowsServerUpgrade"
$managedDiskSKU = "Standard_LRS"

#
# Get the latest version of the special (hidden) VM Image from the Azure Marketplace

$versions = Get-AzVMImage -PublisherName $publisher -Location $location -Offer $offer -Skus $sku | sort-object -Descending {[version] $_.Version }
$latestString = $versions[0].Version

# Get the special (hidden) VM Image from the Azure Marketplace by version - the image is used to create a disk to upgrade to the new version

$image = Get-AzVMImage -Location $location -PublisherName $publisher -Offer $offer -Skus $sku -Version $latestString

#
# Create Resource Group if it doesn't exist
#

if (-not (Get-AzResourceGroup -Name $resourceGroup -ErrorAction SilentlyContinue)) {
    New-AzResourceGroup -Name $resourceGroup -Location $location    
}

#
# Create Managed Disk from LUN 0
#

if ($zone){
    $diskConfig = New-AzDiskConfig -SkuName $managedDiskSKU -CreateOption FromImage -Zone $zone -Location $location
} else {
    $diskConfig = New-AzDiskConfig -SkuName $managedDiskSKU -CreateOption FromImage -Location $location
}

Set-AzDiskImageReference -Disk $diskConfig -Id $image.Id -Lun 0

New-AzDisk -ResourceGroupName $resourceGroup -DiskName $diskName -Disk $diskConfig