Configure a Virtual Machine Scale Set with an existing Azure Load Balancer using Azure PowerShell

In this article, you'll learn how to configure a Virtual Machine Scale Set with an existing Azure Load Balancer.


  • An Azure account with an active subscription. Create an account for free.
  • An existing resource group for all resources.
  • An existing standard sku load balancer in the subscription where the Virtual Machine Scale Set will be deployed.
  • An Azure Virtual Network for the Virtual Machine Scale Set.

Azure Cloud Shell

Azure hosts Azure Cloud Shell, an interactive shell environment that you can use through your browser. You can use either Bash or PowerShell with Cloud Shell to work with Azure services. You can use the Cloud Shell preinstalled commands to run the code in this article, without having to install anything on your local environment.

To start Azure Cloud Shell:

Option Example/Link
Select Try It in the upper-right corner of a code or command block. Selecting Try It doesn't automatically copy the code or command to Cloud Shell. Screenshot that shows an example of Try It for Azure Cloud Shell.
Go to, or select the Launch Cloud Shell button to open Cloud Shell in your browser. Screenshot that shows how to launch Cloud Shell in a new window.
Select the Cloud Shell button on the menu bar at the upper right in the Azure portal. Screenshot that shows the Cloud Shell button in the Azure portal

To use Azure Cloud Shell:

  1. Start Cloud Shell.

  2. Select the Copy button on a code block (or command block) to copy the code or command.

  3. Paste the code or command into the Cloud Shell session by selecting Ctrl+Shift+V on Windows and Linux, or by selecting Cmd+Shift+V on macOS.

  4. Select Enter to run the code or command.


We recommend that you use the Azure Az PowerShell module to interact with Azure. See Install Azure PowerShell to get started. To learn how to migrate to the Az PowerShell module, see Migrate Azure PowerShell from AzureRM to Az.

Sign in to Azure CLI

Sign into Azure with Connect-AzAccount


Deploy a Virtual Machine Scale Set with existing load balancer

Deploy a Virtual Machine Scale Set with New-AzVMss. Replace the values in brackets with the names of the resources in your configuration.

$rsg = <resource-group>
$loc = <location>
$vms = <vm-scale-set-name>
$vnt = <virtual-network>
$sub = <subnet-name>
$lbn = <load-balancer-name>
$pol = <upgrade-policy-mode>
$img = <image-name>
$bep = <backend-pool-name>

$lb = Get-AzLoadBalancer -ResourceGroupName $rsg -Name $lbn

New-AzVmss -ResourceGroupName $rsg -Location $loc -VMScaleSetName $vms -VirtualNetworkName $vnt -SubnetName $sub -LoadBalancerName $lb -UpgradePolicyMode $pol

The below example deploys a Virtual Machine Scale Set with the following values:

  • Virtual Machine Scale Set named myVMSS
  • Azure Load Balancer named myLoadBalancer
  • Load balancer backend pool named myBackendPool
  • Azure Virtual Network named myVnet
  • Subnet named mySubnet
  • Resource group named myResourceGroup

$rsg = "myResourceGroup"
$loc = "East US 2"
$vms = "myVMSS"
$vnt = "myVnet"
$sub = "mySubnet"
$pol = "Automatic"
$lbn = "myLoadBalancer"
$bep = "myBackendPool"

$lb = Get-AzLoadBalancer -ResourceGroupName $rsg -Name $lbn

New-AzVmss -ResourceGroupName $rsg -Location $loc -VMScaleSetName $vms -VirtualNetworkName $vnt -SubnetName $sub -LoadBalancerName $lb -UpgradePolicyMode $pol -BackendPoolName $bep


After the scale set has been created, the backend port cannot be modified for a load balancing rule used by a health probe of the load balancer. To change the port, you can remove the health probe by updating the Azure virtual machine scale set, update the port and then configure the health probe again.

Next steps

In this article, you deployed a Virtual Machine Scale Set with an existing Azure Load Balancer. To learn more about Virtual Machine Scale Sets and load balancer, see: