Provision shielded virtual machines in the VMM fabric

This article describes how to deploy shielded virtual machines in the System Center Virtual Machine Manager (VMM) compute fabric.

You can deploy shielded VMs in VMM in a couple of ways:

• Convert an existing VM into a shielded VM.
• Create a new shielded VM using a signed virtual machine hard disk (VHDX) and optionally a VM template.

Note

You may experience issues deploying a shielded virtual machine over a network with a load balancer or WAN optimization device. It's required for the packet to not be modified during transit for Shielded VMs to successfully deploy.

Before you start

Watch a video that provides a quick, two-minute overview of provisioning shielded VMs in VMM. Then, ensure that you've done the following:

1. Prepare an HGS server: You should have an HGS server deployed. Learn more.

2. Set up VMM: You need to configure global HGS settings in VMM, and set up at least one guarded host. If guarded hosts belong to a cloud, the cloud should be enabled to support shielded VMs. Learn more.

3. Prepare a shielded VHDX and VM template: You should deploy shielded VMs from a shielded virtual hard disk (VHDX), and optionally using a VM template. Learn more about preparing these.

   Note

   You cannot use a service template to create a shielded VM. Use a script instead.

4. Prepare shielding data files: To use the signed template disks in the VMM library, tenants must prepare one or more shielding data files. This file contains all the secrets that a tenant needs to deploy a VM, including the unattend file used to specialize the VM, certificates, and administrator account passwords. The file also specifies which guarded fabric a tenant trusts to host their VM and information about the signed template disks. The file is encrypted and can only be read by a host in a guarded fabric trusted by the tenant. Learn more.

5. Set up host group: For easy management, we recommend that guarded hosts be placed in a dedicated VMM host group.

6. Verify existing VM requirements: If you want to convert an existing VM to shielded, note the following:

   • The VM must be generation 2 and have the Microsoft Windows Secure Boot template enabled
   • The operating system on the disk must be one of:
     • Windows Server 2025, Windows Server 2022, Windows Server 2019
     • Windows 11, Windows 10
   • The OS disk for the VM must use the GUID Partition Table. This is required for generation 2 VMs to support UEFI.

7. Set up helper VHD: The hosting service provider will need to create a VM that acts as a helper VHD for converting the existing machines. Learn more.

Add shielding data files to VMM

Before you can convert an existing VM to a shielded VM or provision a new shielded VM from a template, the VM owner must generate a shielding data file and add it to VMM.

If you don't already have a shielding data file imported, complete the following steps:

1. Create a shielding data file if you don't have one already. Ensure that the shielding data file authorizes the hosting fabric VMM manages to run your shielded VMs.
2. In the VMM console, select Library > Import Shielding Data > Browse and select your shielding data file.
3. Specify a friendly name for the shielding data file in Name and optionally add a description. We recommend that you indicate whether the shielding data file is intended for use with the existing or new VMs in its name to make it easier to find again.
4. Select Import to save the shielding data in VMM.

To manage your imported shielding data files, go to Library > VM Shielding Data (under Profiles).

Provision a new shielded VM

1. Ensure that you have all the prerequisites in place before you start.
2. In VMs and Services, select Create Virtual Machine to open the Create Virtual Machine Wizard.
3. In Select Source, select Use an existing virtual machine, VM template, or virtual hard disk > Browse.
4. Select a shielded VM template or signed template disk. Both are identified by the shield icon .
5. In Select Shielding Data File, select Browse, and select a shielding data file. Only shielding data files that can be used to create a new shielded VM will be shown. Select OK > Next to continue.
6. Follow these instructions to complete the wizard, and to deploy the VM on a host/cloud.

When you complete the wizard, VMM creates a new shielded VM from the disk or template:

1. The template disk (VHDX) file is copied from the VMM library.
2. VM provisioning decrypts the data in the shielding data file, completes any substitution strings in the unattend.xml file, and copies additional files from the shielding data file to the operating system drive (for example, the RDP certificate).
3. The VM restarts, is customized, and re-encrypted with BitLocker. The BitLocker full volume encryption key is stored in the virtual TPM of the new VM.
4. VM customization is complete when the shutdown command in the unattend.xml file runs; the VM remains switched off. If customization gets stuck, check the unattend.xml file by running it on an unshielded VM, or using an encryption-supported shielding data file that allows console access.
5. After VMM detects that specialization has finished, it will update its status to indicate the VM is created and, if selected, start up the VM.

Shield an existing VM

You can enable shielding for a VM currently running on a host in the VMM fabric that isn't guarded.

1. Ensure that you've all the prerequisites in place before you start.
2. Take the VM offline.
3. We recommend that you enable BitLocker on all disks attached to the VM before moving it to the guarded host.
4. Select the VM > Properties > Shield and select a shielding data file.
5. Shut down the VM, export from nonguarded host, and import it to a guarded host. Only a guarded host can access the VM data.

Next steps

Review Manage virtual machine settings to learn how to configure performance and availability settings for VMs.