restrict live migration when users are connected to the VNC console

[Abhishek Kekane]

Users should not be affected due to live migration especially when they are using vnc consoles.

Possible Solution:
A new parameter "force" will be added to the existing live migration api, if it's set to False and user is connected to the VNC console, it won't live migrate that vm.
If "force" parameter is set to True then even if user is connected to VNC console, live migration will be performed.
To detect whether users are connected to the vnc console or not, we can check if the vnc port is opened on the compute node where the vm is running.

[Gary Kotton (garyk)]

Is this related to a specific driver?
I deally the migration should be able to take place and the user will continue to work with the vnc console

[Daniel Berrange (berrange)]

This problem is just a limitation of VNC and should just be documented as such in the appropriate documentation.

A Nova-aware VNC client could use the Nova APIs to detect when a VM was migrated as automatically reconnect again if the VNC connection is lost. As such it would be inappropriate to restrict migration, since Nova cannot tell whether it has a dumb vs intelligent VNC client connected