Multiple VM Creation by ARM Powershell approach - azure

Question

I have a ps workflow(.psm file) where I am trying to create 5 vms in parallel. I am using ARM cmdlets.I am getting an error-
Error- Cannot validate argument on parameter 'SubnetId'. The argument is null or empty. Provide an argument that is not null or empty, and then try the command
again.
Here is my challange-
Even if I remove -parallel parameter from foreach even then its not making any difference.
If I run the same code NOT inside a workflow(ps1 file) removing -parralel parameter I am able to
create 5 vms
Code-
workflow Create-VMs
{
$UserName = "abc#cde.onmicrosoft.com"
$pwd = ConvertTo-SecureString "xxxxxxxx" -AsPlainText -Force
$AzureCredential = New-Object System.Management.Automation.PSCredential($UserName, $pwd)
login-azurermaccount -credential $AzureCredential
Add-AzureRmAccount -Credential $AzureCredential
Select-AzureRmSubscription -SubscriptionName "xxxxx"
$virtualNetworkName = "myvpn"
$locationName = "East US"
$ResourceGroupName = "myrg"
$user = "adminuser"
$password = "AdminPass123"
$VMSize = "Standard_D2"
$sourcevhd = "https://abc.blob.core.windows.net/vhds/windowsserver2008.vhd"
$virtualNetwork = Get-AzureRmVirtualNetwork -ResourceGroupName $ResourceGroupName -Name $virtualNetworkName
foreach -parallel($i in 1..5)
{
$VMName = "myname" + $i
$destinationVhd = "https://abc.blob.core.windows.net/vhds/windowsserver2008" + $i + ".vhd"
$staticip = "dynamicip" + $i
$virtualNetwork = Get-AzureRmVirtualNetwork -ResourceGroupName $ResourceGroupName -Name $virtualNetworkName
$publicIp = New-AzureRmPublicIpAddress -Name $staticip -ResourceGroupName $ResourceGroupName -Location $locationName -AllocationMethod Dynamic
$networkInterface = New-AzureRmNetworkInterface -ResourceGroupName $ResourceGroupName -Name $VMName -Location $locationName -SubnetId $virtualNetwork.Subnets[0].Id -PublicIpAddressId $publicIp.Id
$vmConfig = New-AzureRmVMConfig -VMName $VMName -VMSize $VMSize
$vmConfig = Set-AzureRmVMOSDisk -VM $vmConfig -Name $VMName -VhdUri $destinationVhd -CreateOption FromImage -Windows -SourceImageUri $sourcevhd
$vmConfig = Add-AzureRmVMNetworkInterface -VM $vmConfig -Id $networkInterface.Id
$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
$cred = New-Object System.Management.Automation.PSCredential ($user, $securePassword)
Set-AzureRmVMOperatingSystem -VM $vmConfig -Windows -Credential $cred -ProvisionVMAgent -ComputerName $VMName
New-AzureRmVM -VM $vmConfig -Location $locationName -ResourceGroupName $ResourceGroupName
}
}
Not able to find out what is the actual problem. Any other approach for creating multiple vms in parallel using ARM ?

Answer 1

I've not had much luck with -parallel and the Azure cmdlets, but I can think of two options for you:
1) use PowerShell jobs - this would require you to login for each job, here's a snippet of how I do it - the "job" in this case is removing a resource group.
foreach ($AzureResourceGroup in $AzureResourceGroups) {
Start-Job -Name $AzureResourceGroup {
Param($AzureResourceGroup, $creds, $tenantID, $subscriptionName)
Login-AzureRmAccount -ServicePrincipal -Credential $creds -TenantId $tenantId
Select-AzureRmSubscription -SubscriptionName $subscriptionName
Remove-AzureRMResourceGroup -Force -Verbose -Name $AzureResourceGroup
} -ArgumentList $AzureResourceGroup, $creds, $tenantId, $subscriptionName
}
Get-Job | Wait-Job | Receive-Job
2) I think better way would be to use a JSON template, and have Azure orchestrate the deployment. There's a sample of how of the template and how to do it here: https://github.com/bmoore-msft/AzureRM-Samples/tree/master/VMFromImageMulti - there's a readme in the root to show how to deploy it.