Occasionally, after the host running for a while without any guest VMs running, an attempt to start a VM fails with the following error dialog:
Error starting domain: Unable to create cgroup for VWIN: No such file or directory
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/asyncjob.py", line 45, in cb_wrapper
callback(asyncjob, *args, **kwargs)
File "/usr/share/virt-manager/virtManager/engine.py", line 959, in asyncfunc
File "/usr/share/virt-manager/virtManager/domain.py", line 1128, in startup
File "/usr/lib64/python2.7/site-packages/libvirt.py", line 330, in create
if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: Unable to create cgroup for VWIN: No such file or directory
Once this error occurs, every attempt to start the VM fails with this error. Rebooting the host clears it up, and the VM can be started without any issues after the reboot.
I get this error too... both trying to create a new VM or trying to start an existing one.
Restarting libvirtd seems to fix the issue.
*** This bug has been marked as a duplicate of bug 678555 ***