I just tried running a couple of VMs from virt-manager, and they repeatedly fail, with this traceback: Error starting domain: Unable to read from '/sys/fs/cgroup/machine/cgroup.controllers': No such file or directory Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/asyncjob.py", line 75, in cb_wrapper callback(asyncjob, *args, **kwargs) File "/usr/share/virt-manager/virtManager/asyncjob.py", line 111, in tmpcb callback(*args, **kwargs) File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 66, in newfn ret = fn(self, *args, **kwargs) File "/usr/share/virt-manager/virtManager/object/domain.py", line 1279, in startup self._backend.create() File "/usr/lib64/python3.7/site-packages/libvirt.py", line 1136, in create if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self) libvirt.libvirtError: Unable to read from '/sys/fs/cgroup/machine/cgroup.controllers': No such file or directory There is indeed no /sys/fs/cgroup/machine/cgroup.controllers . There *is*, however, a /sys/fs/cgroup/machine.slice/cgroup.controllers . This is with libvirt-5.6.0-3.fc31.x86_64, systemd-243-1.fc31.x86_64 and kernel 5.3.0-0.rc6.git0.1.fc31.x86_64 . If I can reproduce this on a fresh install it may be a release blocker...
*** This bug has been marked as a duplicate of bug 1751120 ***