Just like it sounds: create a zone then install the VirtualBox package(s). I have my notes for installing a Bugzilla appliance into a zone, if you are interested. The notes are fairly involved, because:
* I think you need VirtualBox installed in the global zone
* You need to import certain devices from the global zone
* You need a startup service to start the virtual machine
* If you want the VM to use a NIC, I found it was easier to allocate a second NIC to the zone, but not have it used by the zone
Watch out for upgrading VirtualBox in the global zone but not upgrading in the local zones. Things get weird.
I don't think you need X or VNC in the local zone if you are comfortable with the command line. You can always RDP to the VM from anywhere.
Indeed I could install Vbox from the downloaded pkg.
But it missed some x11 libs.
I could remember to install a complete system with x11:
pkg install slim_install
And that works, I works as I want:
1 login to zone "vbox"
2 start vncserver
3 connect with vnc client
4 start VirtualBox
5 the VirtualBox manager starts
But this all does a complete install and is a waste of diskspace in a zone.
The global-zone already has x11 installed, can one in some way re-use the
global-zone image in a non-global zone?
I want to be careful not to spoil the global-zone.
I'm not sure what you are trying to accomplish, but slim_install, X and VNC are probably overkill for VirtualBox running in a zone. If you must use the VirtualBox GUI, then yes, you need those things. Otherwise, you can do almost everything with the command line and connect to the guest via an RDP client.