Description of problem: When trying to run a High Performance VM as non headless (via regular run or run-once) and set the graphics protocol to be VNC, the VM failed to start with the following libvirt error: "libvirtError: unsupported configuration: Can't add USB input device. USB bus is disabled" The reason is that VNC protocol requires USB device installed but since USB is automatically disabled for High Performance VMs and there is no UI support for enabling USB then we have a problem. Version-Release number of selected component (if applicable): 4.2 master libvirt-3.7.0-2.fc26.x86_64 vdsm-4.20.3-216.git87725ec52.fc26.x86_64 How reproducible: 100% Steps to Reproduce: 1.Edit or create a VM with 'Optimized for' field set to 'High Performance'. 2.un-check the 'Headless Mode' within the Console tab - to set the VM to non-headless. 3.Save and run this VM. Actual results: The VM failed to run with libvirt error: "libvirtError: unsupported configuration: Can't add USB input device. USB bus is disabled" Expected results: The VM should run with both SPICE and VNC protocol or we should give an option to enable the "OS depended" USB just for High Performance VMs.
This is a known issue that we need to decide how to handle. Maybe just remove the VNC option from graphics protocols pull down menu for HP VMs.
Why don't we just enable Usb silently for VNC? If that's too ugly(but is it?) we can just drop the tablet device
(In reply to Michal Skrivanek from comment #2) > Why don't we just enable Usb silently for VNC? > If that's too ugly(but is it?) we can just drop the tablet device Doesn't USB perform some polling which affects performance?
(In reply to Yaniv Kaul from comment #3) > (In reply to Michal Skrivanek from comment #2) > > Why don't we just enable Usb silently for VNC? > > If that's too ugly(but is it?) we can just drop the tablet device > > Doesn't USB perform some polling which affects performance? It's like with Server/Desktop, it's just a preset so you should be able to override whatever you need. A graphical display might be quite common especially since we ended up with our somewhat complex serial console solution, and VNC is certainly less intrusive than qxl and its set of usb1&2 controllers Again, even if we give up the tablet device it still might be useful to get a glance at the text console in virt-viewer
Okey, so targeting 4.2 to remove the tablet for VNC for HP VMs.
Verified in rhv-release-4.2.1-9-001.noarch the tests performed: Edit VM that was created from a template. Choose 'High Performance' (general tab), uncheck 'Headless' in the console tab, choose VNC graphic protocol. Run VM - ok Change the graphic protocol to SPICE+VNC, stop/start VM. - ok Create new VM, choose 'High Performance', uncheck 'Headless', choose VNC graphic protocol. run once - no error.
This bugzilla is included in oVirt 4.2.0 release, published on Dec 20th 2017. Since the problem described in this bug report should be resolved in oVirt 4.2.0 release, published on Dec 20th 2017, it has been closed with a resolution of CURRENT RELEASE. If the solution does not work for you, please open a new bug report.