Boxgrinder
BoxGrinder Build is an easy to use command line tool to create appliances (virtual images) from simple plaintext appliance definition files. BoxGrinder can produce appliances for a variety of virtual and cloud platforms using plugins supporting technologies such as VMware or EC2.
See the Quick Satrt page (http://boxgrinder.org/tutorials/boxgrinder-build-quick-start/) for an overview of how to use BoxGrinder.
Spice support in virt-manager
With Fedora 15, virt-manager has been updated to support Spice, the complete open source solution for interaction with virtualized desktop. It's now possible to create a virtual machine with Spice support without touching the command line, and benefiting all the Spice enhancements without hassles directly from virt-manager. Thanks to the spice-gtk library, you can also develop a client in Python or C, or with gobject-introspection bindings.
Numerous libvirt improvements
With Fedora 15, libvirt has been updated to support a number of new APIs for interacting with various virtual machines. There is now support for graphics using SPICE, using smartcards with KVM guests, managing SMBIOS fields seen in guests, managing memory and blkio cgroup parameters to limit guest resource usage, support for IPv6 networking to guests, improved auditing, and better debugging of qemu-kvm guests via arbitrary monitor commands.
Xen Pvops Dom0
The Fedora Linux kernel may now provide the basis for a Xen-based virtualization solution. Xen is a hypervisor-based type-1 virtualization platform. The kernel now has the ability to boot in Xen's Dom0, a privileged domain that allows Fedora to provide driver and guest management support to Xen and other non-privileged, guest operating systems.