Generation 2 VMs (preview) on Azure


Generation 2 VMs are currently in public preview. This preview version is provided without a service level agreement, and it's not recommended for production workloads. Certain features might not be supported or might have constrained capabilities. For more information, see Supplemental Terms of Use for Microsoft Azure Previews.

Support for generation 2 virtual machines (VMs) is now available in public preview on Azure. You can't change a virtual machine's generation after you've created it. So, we recommend that you review the considerations here as well as the information on this page before choosing a generation.

Generation 2 VMs support key features that aren't supported on generation 1 VMs, such as: increased memory, Intel® Software Guard Extensions (SGX), and virtual persistent memory (vPMEM). Generation 2 VMs also have some features that aren't supported on Azure yet. For more information, see the Features and capabilities section.

Generation 2 VMs use the new UEFI-based Boot architecture vs the BIOS-based architecture used by generation 1 VMs. Compared to generation 1 VMs, generation 2 VMs may have improved boot and installation times. For an overview of generation 2 VMs and some of the key differences between generation 1 and generation 2, see Should I create a generation 1 or 2 virtual machine in Hyper-V?.

Generation 2 VM sizes

Generation 1 VMs are supported by all VM sizes in Azure. Azure now offers Generation 2 support for the following selected VM series in public preview:

Generation 2 VM images in Azure Marketplace

Generation 2 VMs support the following Azure Marketplace images:

  • Windows Server 2019 Datacenter
  • Windows Server 2016 Datacenter
  • Windows Server 2012 R2 Datacenter
  • Windows Server 2012 Datacenter

On-premises vs Azure generation 2 VMs

Azure does not currently support some of the features that on-premises Hyper-V supports for Generation 2 VMs.

Generation 2 feature On-premises Hyper-V Azure
Secure Boot ✔️
Shielded VM ✔️
vTPM ✔️
Virtualization-Based Security (VBS) ✔️
VHDX format ✔️

Features and capabilities

Generation 1 vs generation 2 features

Feature Generation 1 Generation 2
Disk controllers IDE SCSI
VM Sizes Available on all VM sizes Premium storage supported VMs only

Generation 1 vs generation 2 capabilities

Capability Generation 1 Generation 2
OS disk > 2 TB ✔️
Custom Disk/Image/Swap OS ✔️ ✔️
Virtual machine scale set support ✔️ ✔️
ASR/Backup ✔️
Shared Image Gallery ✔️
Azure Disk Encryption ✔️

Creating a generation 2 VM

Marketplace image

Generation 2 VMs can be created from a marketplace image (which supports UEFI boot) via the Azure portal or Azure CLI.

The windowsserver-gen2preview offer contains Windows generation 2 images only. This avoids confusion with regards to generation 1 vs generation 2 images. To create generation 2 VMs, select Images from this offer and follow the standard VM creation process.

Currently, the following Windows generation 2 images are published in the Azure Marketplace:

  • 2019-datacenter-gen2
  • 2016-datacenter-gen2
  • 2012-r2-datacenter-gen2
  • 2012-datacenter-gen2

See the capabilities section for a list of supported marketplace images as we will continue adding additional images that support Generation 2.

Managed image or managed disk

Generation 2 VMs can be created from managed image or managed disk in the same way you would create a generation 1 VM.

Virtual machine scale sets

Generation 2 VMs can also be created using virtual machine scale sets. You can create generation 2 VMs using Azure virtual machine scale sets via Azure CLI.

Frequently asked questions

  • Are generation 2 VMs available in all Azure regions?
    Yes; however, not all generation 2 VM sizes are available in every region. The availability of generation 2 VMs is dependent upon the availability of the VM size.

  • Is there a price difference between generation 1 and generation 2 VMs?
    There is no difference in pricing between generation 1 and generation 2 VMs.

  • How do I increase the OS disk size?
    OS disks larger than 2 TB are new to generation 2 VMs. By default, most OS disks are less than 2 TB for generation 2 VMs, but the disk size can be increased to a recommended maximum of 4 TB. You can increase the OS disk size via the Azure CLI or the Azure portal. For more information on expanding disks programmatically, see Resize a disk.

    To increase the OS disk size via Azure portal:

    • Navigate to the VM properties page on the Azure portal.

    • Shut down and deallocate the VM using the Stop button on the Azure portal.

    • In the Disks section, select the OS disk that you'd like to increase.

    • Select Configuration in the Disks section and update the Size to the desired value.

    • Navigate back to the VM properties page and Start the VM.

    You may see a warning for OS disks larger than 2 TB. The warning does not apply to generation 2 VMs; however, OS disk sizes larger than 4 TB are not recommended.

  • Do generation 2 VMs support Accelerated Networking?
    Yes, generation 2 VMs support Accelerated Networking.

  • Is .vhdx supported on generation 2?
    No, only .vhd is supported on generation 2 VMs.

  • Do generation 2 VMs support Ultra Solid State Drives (SSD)?
    Yes, generation 2 VMs support Ultra SSD.

  • Can I migrate from generation 1 to generation 2 VMs?
    No, you can't change the generation of a VM after you've created it. If you need to switch between VM generations, you need to create a new VM of a different generation.

Next steps