Abstraction of the underlying virtualization API.
Returns an object representing the connection to a virtualization platform, or to an on-demand bare-metal provisioning platform.
This could be nova.virt.fake.FakeConnection in test mode, a connection to KVM, QEMU, or UML via libvirt_conn, or a connection to XenServer or Xen Cloud Platform via xenapi. Other platforms are also supported.
Any object returned here must conform to the interface documented by FakeConnection.
A string literal that falls through an if/elif structure to determine what virtualization mechanism to use. Values may be