Preparing a Win7 VM for use in Openstack Mitaka

In the project I am currently working on, the client wants to use a variety of OS instances on top of Openstack. Running recent Linux VM's (kernel versions 2.6 and above support the virtio drivers used in Openstack) on Nova just works out of the box, but running Windows VM's on Openstack requires some preparation -- namely, you must first install Redhat's virtio drivers into a Win7 VM and then import the VM image into Glance.

Since I already have a Win7 VM I use for testing in Virtualbox (downloaded legally from Microsoft at modernie), I thought it would be a simple task to just install virtio-win drivers into my Virtualbox Win7 instance. This idea didn't pan out, however.

If you follow the Redhat guide for installing virtio drivers into Windows VM's, your VM needs to have the following System Devices in Device Manager:

• PCI standard RAM Controller (for memory balloon driver)
• PCI Simple Communication Controller (for vioserial driver)
• virtio network (for netKVM driver)
• virtio storage (for viostor driver)

Virtualbox by default supports virtio-net network adapter type, but it doesn't support virtio storage devices, memory ballooning, or vioserial, so these virtio

Here is a screenshot of the available System Devices in a Win7 modernie VM running on Virtualbox:

You will notice that the required devices noted above do not exist.

I therefore had to do things the hard way. First I downloaded a Windows 7 installation iso then I created a new KVM virtual machine using virt-manager. The virtual machine has the following devices:

• 2 IDE CD-ROM's - the first CD-ROM must mount the virtio-win iso file while the second CD-ROM will mount the Windows 7 iso.
• 1 VirtIO hard disk
• 2 VirtIO network adapters (1 for the private subnet, 1 for the public subnet for floating IP's in Openstack)

As of September 2016, you also have to change the video type from QXL to Cirrus, otherwise the VM will get stuck on "Starting Windows". This is a bug in qemu and might have been fixed by the time you read this article.

The Win7 installer will not be able to find any disks (because the disk uses virtio), so when it asks you for the location of the disk, click the install drivers button and select the CD-ROM containing the Redhat virtio drivers for Windows.

I followed this guide for these steps:

https://www.mirantis.com/openstack-portal/express-openstack-portal/migrating-from-vmware-for-windows-vms/

Although the guide is for VMWare, it works just as well for KVM. However, the last step about adding the virtio drivers to regedit is not necessary for KVM.