Expand an existing host pool with new session hosts


This content applies to Azure Virtual Desktop with Azure Resource Manager Azure Virtual Desktop objects. If you're using Azure Virtual Desktop (classic) without Azure Resource Manager objects, see this article.

As you ramp up usage within your host pool, you may need to expand your existing host pool with new session hosts to handle the new load.

This article will tell you how you can expand an existing host pool by adding new session hosts.

What you need to expand the host pool

Before you start, make sure you've created a host pool and session host virtual machines (VMs) using one of the following methods:

You'll also need the following information from when you first created the host pool and session host VMs:

  • Registration token
  • VM size, image, and name prefix
  • Domain join administrator credentials
  • Virtual network name and subnet name

Add virtual machines with the Azure portal

To expand your host pool by adding virtual machines:

  1. Sign in to the Azure portal.

  2. Search for and select Azure Virtual Desktop.

  3. In the menu on the left side of the screen, select Host pools, then select the name of the host pool you want to add virtual machines to.

  4. Select Session hosts from the menu on the left side of the screen.

  5. Select +Add to start adding session hosts to your host pool.

    A screenshot showing the "+Add" option in the portal to add session hosts to a host pool, highlighted with a red border.

  6. If the registration token you used to initially create the host pool has now expired, you'll receive the following banner. Select -> to generate a new registration token. If your host pool's registration token is still valid, skip ahead to step 10.

    A screenshot showing the red banner indicating an invalid registration token highlighted with a red border.

  7. Select Generate new key and select an expiration date. We recommend you set the expiration date to be the maximum of 27 days so that you don't need to regenerate a registration key frequently. Select Ok to generate the registration key.

    A screenshot showing the options to generate a new registration key and set an expiration date for it, highlighted with a red border.

  8. After a few seconds, your host pool's new registration key will get filled in the text box. Select Download and then exit out of the Registration key context blade.

  9. Select +Add once again to start adding session hosts to your host pool.

  10. Ignore the the Basics tab and instead select the Virtual machines tab. Here you can view and edit the details of the virtual machine (VM) you want to add to the host pool.

  11. Select the resource group you want to create the VMs in, then select the region. You can choose the current region the VMs in your host pool are in or a new region.

  12. Enter the number of session hosts you want to add to your host pool into Number of VMs. For example, if you're expanding your host pool by five hosts, enter 5.


    Although it's possible to edit the image and prefix of the VMs, we don't recommended editing them if you have VMs with different images in the same host pool. Edit the image and prefix only if you plan on removing VMs with older images from the affected host pool.

  13. For the Virtual network, select the virtual network and subnet to which you want the virtual machines to be joined. You can select the same virtual network your host pool's existing machines are currently in or choose a different one that's more suitable to the region you selected in step 11.

  14. For the Domain to join, select if you want to join the virtual machines to Active Directory or Azure Active Directory. Selecting Enroll the VM with Intune automatically enrolls the virtual machines in Intune. All virtual machines in a host pool should be joined to the same domain or Azure AD tenant.

  15. For the AD domain join UPN, enter an Active Directory domain username and password associated with the domain you selected. These credentials will be used to join the virtual machines to the Active Directory domain.


    Ensure your admin names comply with info given here. And that there is no MFA enabled on the account.

  16. For the Virtual Machine Administrator account, enter the local administrator account information you want to use for all virtual machines.

  17. Select the Tags tab if you have any tags that you want to group the virtual machines with. Otherwise, skip this tab.

  18. Select the Review + Create tab. Review your choices, and if everything looks fine, select Create.

Next steps

Now that you've expanded your existing host pool, you can sign in to a Azure Virtual Desktop client to test them as part of a user session. You can connect to a session with any of the following clients: