Multiple vNICs in Azure ARM VMs

I have recently faced with a challenge to add multiple vNICs to an ARM based Azure VM. The requirement was to add a secondary vNIC while keeping the first one intact. This post explores how  I achieved this task with PowerShell.

Before you do anything make sure that the existing vNIC Private IP address has been set to static as below. Otherwise once the VM Update operation is completed you will lose that IP address. Optionally you can set the Public IP address to reserved (static) as well. The VM should already have at least two NICs and it is not supported to pass from a single NIC VM to multiple NIC VM and vice versa.

1-vnic-private-ip

2-vnic-public-ip
Create a new vNIC

I have defined the properties for the new vNIC as below.

$VNET = Get-AzureRmVirtualNetwork -Name ‘vmnic-rg-vnet’ -ResourceGroupName ‘vmnic-rg’
$SubnetID = (Get-AzureRmVirtualNetworkSubnetConfig -Name ‘default’ -VirtualNetwork $VNET).Id
$NICName = ‘jcb-vnic02’
$NICResourceGroup = ‘vmnic-rg’
$Location = ‘East US’
$IPAddress = ‘10.0.0.7’

Next step is to create the new vNIC.

New-AzureRmNetworkInterface -Name $NICName -ResourceGroupName $NICResourceGroup -Location $Location -SubnetId $SubnetID -PrivateIpAddress $IPAddress

3-vnic-create

Adding the new vNIC to an existing VM

I’ve executed below PowerShell snippet which sets the existing vNIC as primary and and updates the VM once the new vNIC is in place.

$VMname = ‘jcb-nicvm01’
$VMRG =  ‘vmnic-rg’

$VM = Get-AzureRmVM -Name $VMname -ResourceGroupName $VMRG

$NewNIC =  Get-AzureRmNetworkInterface -Name $NICName -ResourceGroupName $NICResourceGroup
$VM = Add-AzureRmVMNetworkInterface -VM $VM -Id $NewNIC.Id

Then I’m listing the attached NICs in the VM and setting the first one as primary.

$VM.NetworkProfile.NetworkInterfaces

$VM.NetworkProfile.NetworkInterfaces.Item(0).Primary = $true
Update-AzureRmVM -VM $VM -ResourceGroupName $VMRG