Create a VM from a specialized disk

Create a new VM by attaching a specialized disk as the OS disk using Powershell. A specialized disk is a copy of VHD from an exisitng VM that maintains the user accounts, applications and other state data from your original VM. You can use either a specialized managed disk or a specialized unmanaged disk to create the new VM.

Before you begin

If you use PowerShell, make sure that you have the latest version of the AzureRM.Compute PowerShell module. Run the following command to install it.

Install-Module AzureRM.Compute -RequiredVersion 2.6.0

For more information, see Azure PowerShell Versioning.

Create the subNet and vNet

Create the vNet and subNet of the virtual network.

  1. Create the subNet. This example creates a subnet named mySubNet, in the resource group myResourceGroup, and sets the subnet address prefix to

     $rgName = "myResourceGroup"
     $subnetName = "mySubNet"
     $singleSubnet = New-AzureRmVirtualNetworkSubnetConfig -Name $subnetName -AddressPrefix
  2. Create the vNet. This example sets the virtual network name to be myVnetName, the location to West US, and the address prefix for the virtual network to

     $location = "West US"
     $vnetName = "myVnetName"
     $vnet = New-AzureRmVirtualNetwork -Name $vnetName -ResourceGroupName $rgName -Location $location `
         -AddressPrefix -Subnet $singleSubnet

Create a public IP address and NIC

To enable communication with the virtual machine in the virtual network, you need a public IP address and a network interface.

  1. Create the public IP. In this example, the public IP address name is set to myIP.

     $ipName = "myIP"
     $pip = New-AzureRmPublicIpAddress -Name $ipName -ResourceGroupName $rgName -Location $location `
         -AllocationMethod Dynamic
  2. Create the NIC. In this example, the NIC name is set to myNicName.

     $nicName = "myNicName"
     $nic = New-AzureRmNetworkInterface -Name $nicName -ResourceGroupName $rgName `
     -Location $location -SubnetId $vnet.Subnets[0].Id -PublicIpAddressId $pip.Id

Create the network security group and an RDP rule

To be able to log in to your VM using RDP, you need to have an security rule that allows RDP access on port 3389. Because the VHD for the new VM was created from an existing specialized VM, after the VM is created you can use an existing account from the source virtual machine that had permission to log on using RDP. This example sets the NSG name to myNsg and the RDP rule name to myRdpRule.

$nsgName = "myNsg"

$rdpRule = New-AzureRmNetworkSecurityRuleConfig -Name myRdpRule -Description "Allow RDP" `
    -Access Allow -Protocol Tcp -Direction Inbound -Priority 110 `
    -SourceAddressPrefix Internet -SourcePortRange * `
    -DestinationAddressPrefix * -DestinationPortRange 3389
$nsg = New-AzureRmNetworkSecurityGroup -ResourceGroupName $rgName -Location $location `
    -Name $nsgName -SecurityRules $rdpRule

For more information about endpoints and NSG rules, see Opening ports to a VM in Azure using PowerShell.

Set the VM name and size

This example sets the VM name to "myVM" and the VM size to "Standard_A2".

$vmName = "myVM"
$vmConfig = New-AzureRmVMConfig -VMName $vmName -VMSize "Standard_A2"

Add the NIC

$vm = Add-AzureRmVMNetworkInterface -VM $vmConfig -Id $nic.Id

Configure the OS disk

The specialised OS could be a VHD that you uploaded to Azure or a copy the VHD from an existing Azure VM.

You can choose one of two options:

  • Option 1: Create a specialized managed disk from a specialied VHD in an existing storage account to use as the OS disk.


  • Option 2: Use a specialized VHD stored in your own storage account (an unmanaged disk).

Option 1: Create a managed disk from an unmanaged specialized disk

  1. Create a managed disk from the existing specialized VHD in your storage account. This example uses myOSDisk1 for the disk name, puts the disk in StandardLRS storage and uses as the URI for the source VHD.

     $osDisk = New-AzureRmDisk -DiskName "myOSDisk1" -Disk (New-AzureRmDiskConfig `
     -AccountType StandardLRS  -Location $location -CreateOption Import `
     -SourceUri `
     -ResourceGroupName $rgName
  2. Add the OS disk to the configuration. This example sets the size of the disk to 128 GB and attaches the managed disk as a Windows OS disk.

     $vm = Set-AzureRmVMOSDisk -VM $vm -ManagedDiskId $osDisk.Id -StorageAccountType StandardLRS `
     -DiskSizeInGB 128 -CreateOption Attach -Windows

Optional: Attach additional managed disks as data disks. This option assumes that you created your managed data disks using Create managed data disks.

$vm = Add-AzureRmVMDataDisk -VM $VirtualMachine -Name $dataDiskName -CreateOption Attach -ManagedDiskId $dataDisk1.Id -Lun 1

Option 2: Attach a VHD that is in an existing storage account

  1. Set the URI for the VHD that you want to use. In this example, the VHD file named myOsDisk.vhd is kept in a storage account named myStorageAccount in a container named myContainer.

     $osDiskUri = ""
  2. Add the OS disk by using the URL of the copied OS VHD. In this example, when the OS disk is created, the term "osDisk" is appened to the VM name to create the OS disk name. This example also specifies that this Windows-based VHD should be attached to the VM as the OS disk.

     $osDiskName = $vmName + "osDisk"
     $vm = Set-AzureRmVMOSDisk -VM $vm -Name $osDiskName -VhdUri $osDiskUri -CreateOption attach -Windows

Optional: If you have data disks that need to be attached to the VM, add the data disks by using the URLs of data VHDs and the appropriate Logical Unit Number (Lun).

$dataDiskName = $vmName + "dataDisk"
$vm = Add-AzureRmVMDataDisk -VM $vm -Name $dataDiskName -VhdUri $dataDiskUri -Lun 1 -CreateOption attach

When using a storage account, the data and operating system disk URLs look something like this: You can find this on the portal by browsing to the target storage container, clicking the operating system or data VHD that was copied, and then copying the contents of the URL.

Create the VM

Create the VM using the configurations that we just created.

#Create the new VM
New-AzureRmVM -ResourceGroupName $rgName -Location $location -VM $vm

If this command was successful, you'll see output like this:

RequestId IsSuccessStatusCode StatusCode ReasonPhrase
--------- ------------------- ---------- ------------
                         True         OK OK   

Verify that the VM was created

You should see the newly created VM either in the Azure portal, under Browse > Virtual machines, or by using the following PowerShell commands:

$vmList = Get-AzureRmVM -ResourceGroupName $rgName

Next steps

To sign in to your new virtual machine, browse to the VM in the portal, click Connect, and open the Remote Desktop RDP file. Use the account credentials of your original virtual machine to sign in to your new virtual machine. For more information, see How to connect and log on to an Azure virtual machine running Windows.