This is almost certainly the kernel bug mentioned in that Fedora BZ. There is however a workaround added in libvirt now for distros/users who can't fix their kernel https://www.redhat.com/archives/libvir- list/2017-September/msg00519.html
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1722702 Title: libvirt - vnc port selection regression with newer kernels Status in libvirt package in Ubuntu: Confirmed Status in linux package in Ubuntu: Incomplete Bug description: Bug appears in linux-image-4.11.x kernels on 16.04.3. 4.8.x and 4.10.x are okay. When libvirtd is restarted on Kernel 4.11.0-x-generic or above , it loses all information regarding existing port bindings and is unable to correctly re-identify vnc ports that currently in use. libvirt attempts to bind to an existing port and fails. instance-000a6096.log:2017-10-09T01:42:16.017220Z qemu-system-x86_64: -vnc 0.0.0.0:0: Failed to start VNC server: Failed to listen on socket: Address already in use Fairly certain this is the same bug reported, and patched in kernel-4.13.4-200.fc26 for Fedora https://bugzilla.redhat.com/show_bug.cgi?id=1432684 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1722702/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
