Azure VMs fails as public ip is allocated to other resource - azure

Question

I am using a powershell script to create multiple Vms based on an image. The first Vm is ok but when attempting the second Vm I get an error saying that :
| Resource /subscriptions/....../networkInterfaces/xxxxx/ipConfigurations/xxxxx is referencing public IP address
| /subscriptions/xxxxxxxxx/providers/Microsoft.Network/publicIPAddresses/Microsoft.Azure.Commands.Network.Models.PSPublicIpAddress that is already allocated to
| resource /subscriptions/......./networkInterfaces/xxxxx/ipConfigurations/xxxxx.
Here is the script I am using:
param(
[string] $WeekNo="NoWeek",
[int] $VmCount=0
)
#$cred = Get-Credential -Message "Enter a username and password for the virtual machine."
## VM Account
# Credentials for Local Admin account you created in the sysprepped (generalized) vhd image
$VMLocalAdminUser = "xxxxx"
$VMLocalAdminSecurePassword = ConvertTo-SecureString "xxxxxxx" -AsPlainText -Force
$image = "/subscriptions/xxxxxxx/resourceGroups/xxxxxx/providers/Microsoft.Compute/images/xxxxxxxxx"
## Azure Account
$LocationName = "SwedenCentral"
$ResourceGroupName = "xxxx_" + $WeekNo
if( -Not( Get-AzureRmResourceGroup -Name $ResourceGroupName -Location $LocationName -ErrorAction Ignore)) {
New-AzureRmResourceGroup -Name $ResourceGroupName -Location $LocationName
Write-Host "ResourceGroup" $ResourceGroupName "created"
$VMSize = "Standard_B2ms"
## Networking
$NetworkName = "xxxxxx_" + $WeekNo + "_net" # "MyNet"
$SubnetName = "MySubnet"
$SubnetAddressPrefix = "10.0.0.0/24"
$VnetAddressPrefix = "10.0.0.0/16"
$SingleSubnet = New-AzVirtualNetworkSubnetConfig -Name $SubnetName -AddressPrefix $SubnetAddressPrefix
$Vnet = New-AzVirtualNetwork -Name $NetworkName -ResourceGroupName $ResourceGroupName -Location $LocationName -AddressPrefix $VnetAddressPrefix -Subnet $SingleSubnet
}
$Credential = New-Object System.Management.Automation.PSCredential ($VMLocalAdminUser, $VMLocalAdminSecurePassword);
$VMName = "xxxx" + $WeekNo
##New-AzVM -ResourceGroupName $ResourceGroupName -Location $LocationName -VM $VirtualMachine -Verbose -Image $image
for($i=1; $i -le $VmCount; $i++){
$VMBaseName = "iCPSEDU" + $WeekNo + $i
$StorageAccount = "xxxxx" + $WeekNo + $i
$PublicIPAddressName = $VMBaseName + "PIP$(Get-Random)"
$NICName = $VMBaseName + "NIC"
$DNSNameLabel = "xxxx" + $WeekNo + $i + "dns" # mydnsname.westus.cloudapp.azure.com
$PIP = New-AzPublicIpAddress -Name $PublicIPAddressName -DomainNameLabel $DNSNameLabel -ResourceGroupName $ResourceGroupName -Location $LocationName -AllocationMethod Dynamic
$NIC = New-AzNetworkInterface -Name $NICName -ResourceGroupName $ResourceGroupName -Location $LocationName -SubnetId $Vnet.Subnets[0].Id -PublicIpAddressId $PIP.Id
Write-Host "Creating VM " $VMBaseName
New-AzVm `
-ResourceGroupName $ResourceGroupName `
-Name $VMBaseName `
-ImageName $image `
-Location $LocationName `
-VirtualNetworkName $Vnet `
-SubnetName $SubnetName `
-SecurityGroupName "myImageNSG" `
-PublicIpAddressName $PIP -Credential $Credential -Size $VMSize -PublicIpSku Standard
Write-Host "VM " $VMBaseName " Created"
Stop-AzVM -ResourceGroupName $ResourceGroupName $VMBaseName -Force -NoWait
Write-Host "VM " $VMBaseName " Stopped"
}
Write-Host "Done."`
To me it seems that the variable used for the PIP is not "flushed" properly between the executions but I have no idea on how to do this?
Or is there something else causing the error?
I have tried adding some delays but without effect.

Answer 1

Create a public IP address and specify a DNS name
Create a NSG
Create a NIC and associate with created pub IP address and NSG
Create a virtual machine configuration and assign the NIC
Create the VM with the config
https://github.com/Azure/azure-docs-powershell-samples/blob/master/virtual-machine/create-vm-detailed/create-windows-vm-detailed.ps1
rough summary of important steps:
$pip = New-AzPublicIpAddress -ResourceGroupName $resourceGroup -Location $location `
-Name "mypublicdns$(Get-Random)" -AllocationMethod Static -IdleTimeoutInMinutes 4
$nsg = New-AzNetworkSecurityGroup -ResourceGroupName $resourceGroup -Location $location `
-Name myNetworkSecurityGroup -SecurityRules $nsgRuleRDP
$nic = New-AzNetworkInterface -Name myNic -ResourceGroupName $resourceGroup -Location $location `
-SubnetId $vnet.Subnets[0].Id -PublicIpAddressId $pip.Id -NetworkSecurityGroupId $nsg.Id
$vmConfig = New-AzVMConfig -VMName $vmName -VMSize Standard_D1 | `
Set-AzVMOperatingSystem -Windows -ComputerName $vmName -Credential $cred | `
Set-AzVMSourceImage -PublisherName MicrosoftWindowsServer -Offer WindowsServer -Skus 2016-Datacenter -Version latest | `
Add-AzVMNetworkInterface -Id $nic.Id
New-AzVM -ResourceGroupName $resourceGroup -Location $location -VM $vmConfig
MS is providing well tested powershell code for various tasks:
I prefer the github samples https://github.com/Azure/azure-docs-powershell-samples over the steps in learn and doc.microsoft.com
also have a deeper look at the Azure CLI examples and template based deployments. It seems to me that MS is abandoning PS a bit.