Unable to Deploy Windows VM Using ISO With AMD-Based CPU

Problem

Windows VM using ISO is failing with the following error in the PCD UI on hypervisor with AMD-based CPU.

Exceeded maximum number of retries. Exhausted all hosts available for retrying build failures for instance [UUID].

Traceback (most recent call last):

File "/var/lib/openstack/lib/python3.10/site-packages/nova/conductor/manager.py", line 705, in build_instances

raise exception.MaxRetriesExceeded(reason=msg)

nova.exception.MaxRetriesExceeded: Exceeded maximum number of retries. Exhausted all hosts available for retrying build failures for instance [UUID].

Environment

• Private Cloud Director - Virtualisation: v2025.4 and Higher.

• Self-Hosted Private Cloud Director - Virtualisation: v2025.4 and Higher.

• Component - Compute Service

Cause

The failure occurs because the guest XML generated during instance creation is attempting to enable a feature called Hyper-V Enlightened VMCS (hv-evmcs). This feature is specific to Intel processors and is not supported on AMD CPUs.

File "/usr/lib/python3/dist-packages/libvirt.py", line 1385, in createWithFlags\n    raise libvirtError(\'virDomainCreateWithFlags() failed\')\n', 'libvirt.libvirtError: internal error: qemu unexpectedly closed the monitor: [TIMESTAMP] qemu-system-x86_64: Hyper-V enlightened VMCS (hv-evmcs) is not supported by kernel\n'

Resolution

To prevent the use of hv-evmcs when launching instances on AMD-based hosts, update the image metadata to disable Hyper-V enlightenments:

openstack image set --property hw_machine_type=q35 <IMAGE_ID>
openstack image set --property hw_cpu_hyperv=off <IMAGE_ID>