It is set to ``reboot`` by default.
+cpu\_cores
+ Valid for the KVM hypervisor.
+
+ Number of emulated CPU cores.
+
+cpu\_threads
+ Valid for the KVM hypervisor.
+
+ Number of emulated CPU threads.
+
+cpu\_sockets
+ Valid for the KVM hypervisor.
+
+ Number of emulated CPU sockets.
+
The ``-O (--os-parameters)`` option allows customisation of the OS
parameters. The actual parameter names and values depends on the OS