Re: [Qemu-devel] vnc port selection

[Anthony Liguori]

Avi Kivity wrote:
> Gerd Hoffmann wrote:
> >   Hi folks,
> >
> > Xen's qemu-dm version has a '-vncunused' command line switch which asks
> > the internal vnc server to pick any unused tcp port to listen on.  The
> > actual port is communicated to the outside world via xenstore.
> >
> > I'm looking for a reasonable way to implement that functionality in
> > upstream qemu.  First, I think it shouldn't be a separate command line
> > switch but an option for the existion -vnc switch.  Second, we need a
> > way to communicate the port picked which isn't xen-specific.  Obvious
> > choice is a monitor info subcommand.
> >
> > Comments?  Other suggestions?
> >
> >   
>
> Presumably -vncunused is passed by the management application, which 
> knows about all domains.  Can't it figure out an unused port and pass 
> it on?

An argument for this sort of semantics is that if you just launch 
vncserver with no argument, it'll sit on the first unused port.  So 
people are sort of used to this behavior.

> Alternatively, have the management application pass an fd denoting the 
> socket.

If you are allocating the ports in the management tool, then just tell 
QEMU what port to open up.  I don't think you gain anything passing an fd.

Regards,

Anthony Liguori