In my previous article I went over why and when we sometimes face capacity issues in Azure while trying to provision Virtual Machines : Understanding and Overcoming Azure VM SKU Capacity Limitations.
In this article I want to share more advanced automation to deal with that task automatically:
Scripted SKU Availability Testing
To help assess which SKUs are currently available in specific zones, you can use a PowerShell script that:
- Lists available VM SKUs in your selected region.
- Tests zonal provisioning via
-WhatIfsimulation. - Helps you proactively plan capacity before scaling or migrating workloads.
This script is especially helpful when preparing infrastructure for:
- Production launches
- Lift-and-shift migrations
- Scaling workloads into new zones
Feel free to use and tweek according to your needs:
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| <# | |
| .AUTHOR | |
| Vukasin Terzic | |
| https://azureis.fun | |
| #> | |
| function Get-AzVMSKUAvailabilityInZone { | |
| [CmdletBinding()] | |
| param ( | |
| [Parameter(Mandatory = $true)] | |
| [string]$Region, | |
| [Parameter(Mandatory = $true)] | |
| [string]$ResourceGroupName, | |
| [Parameter(Mandatory = $false)] | |
| [string[]]$Skus, | |
| [Parameter(Mandatory = $false)] | |
| [string]$ExportCsvPath, | |
| [Parameter(Mandatory = $false)] | |
| [switch]$CleanUpAfter | |
| ) | |
| # Ensure Az module is available | |
| if (-not (Get-Module -ListAvailable -Name Az.Compute)) { | |
| Write-Error "Az.Compute module not found. Please install the Az module first." | |
| return | |
| } | |
| # Create Resource Group if it doesn't exist | |
| if (-not (Get-AzResourceGroup -Name $ResourceGroupName -ErrorAction SilentlyContinue)) { | |
| Write-Host "Creating resource group '$ResourceGroupName' in region '$Region'..." | |
| New-AzResourceGroup -Name $ResourceGroupName -Location $Region | Out-Null | |
| Start-Sleep -Seconds 5 # Wait for resource group to be created | |
| } else { | |
| Write-Host "Using existing Resource group '$ResourceGroupName'." | |
| } | |
| # Create test networking resources | |
| $vnetName = "vmtest-vnet1" | |
| $subnetName = "vmtest-subnet1" | |
| $vnet = Get-AzVirtualNetwork -Name $vnetName -ResourceGroupName $ResourceGroupName -ErrorAction SilentlyContinue | |
| if (-not $vnet) { | |
| Write-Host "Creating test VNet and Subnet..." | |
| $subnetConfig = New-AzVirtualNetworkSubnetConfig -Name $subnetName -AddressPrefix "10.0.0.0/24" | |
| $vnet = New-AzVirtualNetwork -Name $vnetName -ResourceGroupName $ResourceGroupName -Location $Region -AddressPrefix "10.0.0.0/16" -Subnet $subnetConfig | |
| } else { | |
| Write-Host "Using existing VNet '$vnetName' and Subnet '$subnetName'..." | |
| } | |
| $subnet = $vnet.Subnets[0] | |
| # Check if the region is valid | |
| Write-Host "Validating region '$Region'..." | |
| $validRegions = Get-AzLocation | Select-Object -ExpandProperty Location | |
| if ($Region -notin $validRegions) { | |
| Write-Error "The specified region '$Region' is not valid. Available regions are: $($validRegions -join ', ')" | |
| return | |
| } | |
| # Get available VM SKUs | |
| Write-Host "Fetching VM SKUs for region '$Region'..." | |
| $allSkus = Get-AzComputeResourceSku | Where-Object { $_.Locations -contains $Region -and $_.ResourceType -eq "virtualMachines" } | |
| # Validate user-supplied SKUs | |
| if ($Skus) { | |
| $availableSkuNames = $allSkus.Name | |
| $notFoundSkus = $Skus | Where-Object { $_ -notin $availableSkuNames } | |
| if ($notFoundSkus.Count -gt 0) { | |
| Write-Warning "The following SKUs were not found or are not available in region '$Region': $($notFoundSkus -join ', ') and will be ignored." | |
| } | |
| $filteredSkus = $allSkus | Where-Object { $Skus -contains $_.Name } | |
| } else { | |
| $filteredSkus = $allSkus | |
| } | |
| $results = @() | |
| # Generate temporary random credentials | |
| function New-RandomPassword { | |
| param([int]$length = 16) | |
| $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%&*' | |
| -join ((1..$length) | ForEach-Object { $chars | Get-Random }) | |
| } | |
| $adminUsername = "vmadmin" | |
| $adminPassword = ConvertTo-SecureString (New-RandomPassword) -AsPlainText -Force | |
| $cred = New-Object System.Management.Automation.PSCredential ($adminUsername, $adminPassword) | |
| foreach ($sku in $filteredSkus) { | |
| $zones = $sku.LocationInfo | Where-Object { $_.Location -eq $Region } | Select-Object -ExpandProperty Zones | |
| if ($zones) { | |
| foreach ($zone in $zones) { | |
| $vmName = "vmtest-$($sku.Name.ToLower())-z$zone" | |
| $nicName = "$vmName-nic" | |
| try { | |
| Write-Host "Creating NIC for $vmName ..." | |
| $nic = New-AzNetworkInterface -Name $nicName -ResourceGroupName $ResourceGroupName -Location $Region -SubnetId $subnet.Id -ErrorAction Stop | |
| $vmConfig = New-AzVMConfig -VMName $vmName -VMSize $sku.Name -Zone $zone | |
| $vmConfig = Set-AzVMOperatingSystem -VM $vmConfig -Windows -ComputerName $vmName -Credential $cred -ProvisionVMAgent -EnableAutoUpdate | |
| $vmConfig = Set-AzVMSourceImage -VM $vmConfig -PublisherName "MicrosoftWindowsServer" -Offer "WindowsServer" -Skus "2019-Datacenter" -Version "latest" | |
| $vmConfig = Add-AzVMNetworkInterface -VM $vmConfig -Id $nic.Id | |
| #Disable boot diagnostics by not attaching a diagnostics profile. Otherwise it will require storage account. | |
| Write-Host "Disabling boot diagnostics for $vmName ..." | |
| $vmConfig.DiagnosticsProfile = $null | |
| Write-Host "Testing provisioning of $vmName in zone $zone using WhatIf..." | |
| $whatIf = New-AzVM -ResourceGroupName $ResourceGroupName -Location $Region -VM $vmConfig -WhatIf -ErrorAction Stop | |
| $results += [PSCustomObject]@{ | |
| VMSize = $sku.Name | |
| Zone = $zone | |
| AvailableInZone = $true | |
| ProvisionableNow = $true | |
| } | |
| } | |
| catch { | |
| Write-Warning "Provisioning test failed for $($sku.Name) in zone $zone : $($_.Exception.Message)" | |
| $results += [PSCustomObject]@{ | |
| VMSize = $sku.Name | |
| Zone = $zone | |
| AvailableInZone = $true | |
| ProvisionableNow = $false | |
| } | |
| } | |
| # Cleanup NIC | |
| Write-Host "Cleaning up NIC: $nicName" | |
| Remove-AzNetworkInterface -Name $nicName -ResourceGroupName $ResourceGroupName -Force -ErrorAction SilentlyContinue | |
| } | |
| } | |
| else { | |
| $results += [PSCustomObject]@{ | |
| VMSize = $sku.Name | |
| Zone = "-" | |
| AvailableInZone = $false | |
| ProvisionableNow = $false | |
| } | |
| } | |
| } | |
| if ($ExportCsvPath) { | |
| Write-Host "Exporting results to $ExportCsvPath" | |
| $results | Export-Csv -Path $ExportCsvPath -NoTypeInformation | |
| } | |
| # Optional cleanup of entire resource group | |
| if ($CleanUpAfter) { | |
| Write-Host "Cleaning up entire resource group '$ResourceGroupName'..." | |
| Remove-AzResourceGroup -Name $ResourceGroupName -Force -AsJob | |
| } else { | |
| Write-Host "Test completed. Resource group '$ResourceGroupName' retained for review." | |
| } | |
| return $results | |
| } | |
| # Example usage | |
| Get-AzVMSKUAvailabilityInZone -Region "eastus2" -ResourceGroupName "TempRG1" -Skus "Standard_D4s_v5", "Standard_D8s_v5" -ExportCsvPath "C:\Temp\Report.csv" -CleanUpAfter |
The result you will receive will look like this:
In case you have any questions feel free to reach out.
Thanks for reading and keep clouding around.
Vukasin Terzic