Hyper-V UEFI SecureBoot¶
Secure Boot is a mechanism that starts the bootloader only if the bootloader’s signature has maintained integrity, assuring that only approved components are allowed to run. Secure Boot is dependent on UEFI.
Secure Boot is currently disabled in the Nova Hyper-V Driver, as it did not support Linux guests , only Windows guests . The new Windows / Hyper-V Server Technical Preview introduces Secure Boot support for Linux guests. 
This feature will increase the security of the spawned instances, assuring their integrity before they boot.
In order enable Secure Boot on an instance, the field SecureBootEnabled must be set to True, when creating the instance’s Msvm_VirtualSystemSettingData WMI object.
As Secure Boot is not supported by all guests, enabling it for instances that
do not support it will result in a hanging VM. Thus, Secure Boot feature will
be enabled by setting the
os_secure_boot image property or the
os:secure_boot flavor extra spec to
required. Other possible values
optional. The flavor extra spec value overrides the
image property value.
The image property values are:
disabled, optional, required. If the
property is not defined, the default value
disabled will be used.
The flavor extra spec acceptable value is:
required. Any other value will
Linux guests are supported in Windows / Hyper-V Server Technical Preview and
they also require the bootloader’s digital signature. This will also be
provided as an image property
If the given instance requires Secure Boot but it does not contain the
hw_machine_type=hyperv-gen2 image property, the instance creation should
fail, as Secure Boot requires Generation 2 VMs. Generation 2 VMs were
introduced in Windows / Hyper-V Server 2012 R2 and support for them was
introduced in the Kilo release (see Dependencies section).
Scheduling is assured by the ImagePropertiesFilter , which checks if the
hypervisor_version_requires is satisfied by the given
hosts. This is the initial approach to solving the scheduling problem. Ideally,
this problem will be solved by exposing this feature as a host capability and
os_type image properties match the host
Data model impact¶
os_secure_boot field must be added to the ImageMetaProps object, as there
is no field for the image property with the same name.
REST API impact¶
This feature will assure that the spawned instances are safe.
Other end user impact¶
Other deployer impact¶
The images must be prepared for Secure Boot. For example, the VM on which the image is prepared, it must be Generation 2 VM with Secure Boot enabled. Instances using such images will be able to spawned with Secure Boot on or off, while instances using images that are not prepared for Secure Boot can only spawn with Secure Boot off.
Images should be for Generation 2 VMs images. The image property
hw_machine_type=hyperv-gen2 is mandatory.
Linux images requiring Secure Boot must be spawned on Windows / Hyper-V Server
Technical Preview. In order for the instances to be properly scheduled, the
images must contain the property
this case, the image property
os_secure_boot_signature containing the
bootloader’s digital signature is required.
Nova scheduler should use the ImagePropertiesFilter , which checks that the
hosts satisfy the
hypervisor_version_requires image property. In order to
use this filter, it should be added to the scheduler’s nova.conf file,
scheduler_default_filters field. By default, this filter is included in the
In order to properly use Secure Boot, images should be created as follows:
Windows images (Windows 8 or Windows / Hyper-V Server 2012 R2 or newer):
- glance image-create –property hypervisor_type=hyperv
–property hw_machine_type=hyperv-gen2 –property hypervisor_version_requires=’>=6.3’ –property os_secure_boot=required –name win-secure –disk-format vhd –container-format bare –file path/to/windows.vhdx
glance image-update –property hw_machine_type=hyperv-gen2 win-secure
glance image-update –property os_secure_boot=required win-secure
glance image-update –property hypervisor_version_requires=’>=6.3’ win-secure
- glance image-create –property hypervisor_type=hyperv
–property hw_machine_type=hyperv-gen2 –property hypervisor_version_requires=’>=10.0’ –property os_secure_boot=required –property os_secure_boot_signature=$SIGNATURE –name im-secure –disk-format vhd –container-format bare –file path/to/linux.vhdx
glance image-update –property hw_machine_type=hyperv-gen2 im-secure
glance image-update –property os_secure_boot=required im-secure
glance image-update –property os_secure_boot_signature=$SIGNATURE im-secure
glance image-update –property hypervisor_version_requires=’>=10.0’ im-secure
os_secure_boot image property acceptable values are:
disabled, optional, required. If the property is not defined,
will be used as default value. The
optional value means that the image is
capable of Secure Boot, but it will require the flavor extra spec in order to
use this feature.
Secure Boot VMs can also be requested as a flavor extra spec called
os:secure_boot, having the value
nova flavor-key m1.your.flavor set “os:secure_boot=required”
As described in the Proposed Change.
- Hyper-V VM Generation 2 nova spec. Feature merged in Kilo.
Will be tested by Hyper-V CI.
The new image properties and will have to be documented.
-  Hyper-V Generation 2 VMs
-  Secure Boot not supported on:
-  Secure Boot supported on:
- Ubuntu, SUSE on Hyper-V Technical Preview:
-  Msvm_VirtualSystemSettingData:
-  Nova scheduler ImagePropertiesFilter: