Preparing VMs for Conversion to OpenStack - For Windows VMs that Run in VMware

Before you perform a backup operation for Windows virtual machines that you plan to convert, prepare the VMs for conversion to OpenStack.

Before You Begin

  • Note that virtual machines running the following guest operating systems can be converted to OpenStack instances:

    • Window Server 2019

    • Window Server 2016

    • Windows 2012 R2

    • Windows 2008 R2

  • If the source VM has more than four disks, do the following:

    • Install VirtIO drivers on source VMs, to ensure that the instance will be bootable after conversion.

    • Override the controller type by adding the additional setting sConvertControllerTypeTo to the source VM, and then setting the value of the additional setting to scsi or virtio. For more information, see Overriding the Controller Type.

  • If the source VM contains a device entry in etc/fstab in the following format:

    /dev/device_name mountpoint fs_type mount_args

    then change the entry in the source VM to use the following format instead:

    UUID=fs_uuid mountpoint fs_type mount_args

    You can run the lsblk -f command on the source VM to return a list of the UUIDs for block devices in the source VM.

  • To convert a VM with more than four disks, libvirt version 1.3.3 or later is required on the destination Nova compute nodes for the converted OpenStack instance.

    Red Hat Bug 1343302 reports an issue with attaching more volumes for earlier libvirt versions.

  • Perform a full VM backup of the VMware (source) virtual machines.


If the source VM has more than four disks, make changes to the source VMs to ensure that they can be converted successfully.

  1. For Windows VMs that run in VMware, inject drivers for the SCSI controller (vioscsi) and network adapter (netkvm) so that the OpenStack instance can start after conversion.

    The vioscsi driver is required for the Windows boot process.

    1. Perform the following steps for both of the driver files (vioscsi.inf and netkvm.inf):

      1. Go to Run and execute hdwwiz.exe to open the Add New Hardware wizard.

      2. Select Install the hardware that I manually select from a list.

      3. Select Show All Devices as the hardware type.

      4. Click Have Disk.

        The Install from Disk dialog box appears.

      5. Select the driver file, and then click OK.

      6. Click Next to continue, click Next again to start installing the driver, and then click Finish when the installation completes.

    2. From Windows Explorer, right-click the vioscsi.inf file, and then click Install.

    3. From Windows Explorer, right-click the netkvm.inf file, and then click Install.

    4. To add the VirtIO SCSI controller to the CriticalDeviceDatabase, add the following registry key to the Windows registry hive:

      [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\PCI#VEN_1AF4 & DEV_1004 & SUBSYS_00081AF4 & REV_00] "ClassGUID" = "{4D36E97B-E325-11CE-BFC1-08002BE10318}" "Service" = "vioscsi"


      • If the CriticalDatabase folder does not already exist, create one.

      • "ClassGUID" and "Service" are string values.

  2. Perform a backup operation for the modified source VMs.