[Qemu-discuss] Virtual desktops network and port numbers

[Lucio Crusca]

Hello,

I'm planning a local network where all the desktops are virtual guests 
used over SPICE. There is requirement I need to address, and I don't 
understand how. It's the fact that each user must be able to use his/her 
guest from each client.

I don't know if this requirement already has a specific name and a 
common solution, it seems to me a very common requirement, however I 
fail to understand what the solution is, when using 
qemu+kvm+libvirt+spice, so I'll try to explain the problem in more detail.

Let's say Joe today sits at client4 and he wants to use his virtual 
desktop, namely guest9. Server side, guest9 is a virtual machine 
listening over spice at TCP port 3051. That means remote-viewer on 
client4 should ask Joe for authentication and then connect to the server 
using port 3051, because Joe's desktop is the one named guest9, which is 
listening on port 3051. How does remote-viewer become aware of the 
correct port number for Joe?

I understand there's something basically wrong in my reasoning, because 
remote-viewer needs a port to connect to before authentication even 
starts, so there must be something in the spice protocol that somehow 
multiplexes a single port to many guest, RPC portmapper style, but I've 
failed to find even a faded trace of it in the docs...