Enable Accelerated Networking on existing Azure VM’s

In this post we will go over the different methods to enabled accelerated networking in an existing Azure VM.

Accelerated networking improves performance as it allows the network interfaces of Azure VM to bypass the host.

Screen shot from Microsoft documentation

Below are some of the benefits of using accelerated network.

Lower Latency / Higher packets per second

Reduced jitter,

Decreased CPU utilization

Accelerated networking is only supported on VM that have 2 or more CPU’s. If the VM’s are in a availability set all VM’s in the set need to be powered off before updating.

There are three way’s to enabled accelerated networking on existing VMs use either AZ PowerShell Module or the AZ CLI and directly in the Azure portal.

To enable in the Azure portal go to Virtual machines > Networking and select the required network interface.

To enable first Power off the VM,

Select the network interface and click on the name. This will bring you to the network interface configuration page.

Click on enable accelerated networking

You will have to confirm you have validate that your operating system is supported.

Once completed the network interface should now show have accelerated networking enabled.

Enabling in the console is fine for one or two interfaces but if there are a few to update doing PowerShell or AZ CLI will be a quicker method.

To update using the AZ PowerShell Module, first we need to install the module.

To install run the below command

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
Install-Module -Name Az -Scope CurrentUser -Repository PSGallery -Force

Once installed use the below to connect, you will be prompted to put in Azure account details.

Connect-AzAccount

Once connected, we can check if the network interfaces have accelerated networking using the below command.

Get-AzNetworkInterface -ResourceGroupName RGName | Select-Object Name,EnableAcceleratedNetworking

To enabled accelerated networking the VM needs to be stopped and deallocated so either power off from the Azure console or use stop-azvm

Stop-AzVM  -Name VMName -ResourceGroupName RGName

To enable we need to get the network adapter information into a variable and then set the enabledacceleratednetworking property to true.

$networkacc = Get-AzNetworkInterface -ResourceGroupName RGName-Name nicname
$networkacc.EnableAcceleratedNetworking = $true
$networkacc | Set-AzNetworkInterface

Once the command completes, we can run the command to check the network interfaces again and one should now have enabledaccleratednetworking set to true.

If there were multiple network interfaces in the resource group to enable, we could get the list and loop through each, but each VM would need to be supported or they would error out.

$networkaccs = Get-AzNetworkInterface -ResourceGroupName RGName
foreach ($networkacc in $networkaccs){

$networkacc.EnableAcceleratedNetworking = $true
$networkacc | Set-AzNetworkInterface

}

Last step is to power back on the VM either from the Azure portal or using AZ PowerShell.

Start-AzVM  -Name VMName -ResourceGroupName RGName

That is the process for setting using AZ Powershell.

To set using the Azure CLI, first we need to install the go to the below and download the MSI installer.

https://docs.microsoft.com/en-us/cli/azure/install-azure-cli-windows?tabs=azure-cli

Once installed launch PowerShell.

to logon either use az login for an interactive logon process

or use with username and password parameter. (This method will not work with MFA so we will be using the interactive method.)

az login -u <username> -p <password>

When running the az login command you will be brought to the standard login.microsoft.com page.

Once signed in, we can query the resource group for network interfaces to see what has acceleratednetworking enabled

az network nic list --resource-group RGName --query [].[name,enableAcceleratedNetworking] --output table

To update the interfaces the VM needs to be powered off either in the Azure console or using AZ Cli

To use AZ Cli

az vm deallocate --resource-group RGName --name VMName
az network nic update --name NicName --resource-group RGName --accelerated-networking true

Once the command completes run the list command again to confirm that acceleratednetworking is set to true.

last step is to start the VM using either Azure port or Az Cli

az vm start --resource-group RGName --name VMName

The network interfaces should now have accelerated networking enabled.

Azure Configure vNet peering

To allow communication between vNet’s in Azure we can set up peering connections. This is useful if there is a need to have different vNet’s for things like web app’s and backend database zones.

To configure peering we will require two different vNets both must be in the same Azure region.

Currently when I try to ping a VM that is running in a different vNet there is no communication.vNet01

Logon to Azure

Go to All services > Virtual networksvNet04

Once in Virtual networks select the network that will be configure for peeringvNet02

Once the network blade is open go to peering > AddvNet03

Enter a Name, select the Subscription that the other vNet is in. Then Select the Virtual Network. Under configuration select Enabled and the last step tick Allow forwarded trafficvNet05

Below are some details on three options:

Allow forwarded traffic: This setting allows the peer’s forwarded traffic (traffic not originating from inside the peer virtual network) into your virtual network.
Allow gateway transit: Allows the peer virtual network to use your virtual network gateway. The peer virtual network cannot already have a gateway configured, and must select ‘use remote gateway’ in its peering settings.
Use remote gateway: You will need to Select this option if you wish to use your peer’s virtual network gateway. The peer virtual network must have a gateway configured, as well as ‘allow gateway transit’ enabled. Only one peering in this virtual network can have this enabled. You cannot use this setting if you already have a gateway configured in your virtual network.

Once all settings are confirmed click ok to create the peeringvNet06vNet07

Two allow communication both ways, there will need to peering setup on the App network aswell.

Once both are enabled we can now see response to ping requestsvNet08

To lock down communication between the networks we can add NSG’s to restricted what inbound and outbound traffic is allowed from the subnet’s.