Hi Alessio,
I just tested it and it seems to be working without a problem.
To explain the examples which you sent, might help.
The `next_run: true` "prepares" the VM parameters and after reboot, the parameters will be set.
I noticed that you did not set any parameter to the VM in that task, so it has nothing to do.
And as for the second example, with `state: next_run`, this updates the parameters and reboots automatically.
Please check out if the VM does not already have boot_devices set to hard disk.
Martin Necas