Hi, As explained in a bug on the debian BTS[0], I'm getting the following backtrace on my machine when trying to start a domain: Erreur lors du démarrage du domaine: At least one cgroup controller is required: No such device or address Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/asyncjob.py", line 96, in cb_wrapper callback(asyncjob, *args, **kwargs) File "/usr/share/virt-manager/virtManager/asyncjob.py", line 117, in tmpcb callback(*args, **kwargs) File "/usr/share/virt-manager/virtManager/domain.py", line 1160, in startup self._backend.create() File "/usr/lib/python2.7/dist-packages/libvirt.py", line 697, in create if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self) libvirtError: At least one cgroup controller is required: No such device or address This is only happening when /sys/fs/cgroup/systemd is being mounted by logind while systemd is not acting as the init system. I've been asked by danpb to report the following information on this mailing list: $ cat /proc/mounts|grep cgroup none /sys/fs/cgroup tmpfs rw,rootcontext=system_u:object_r:sysfs_t:s0,seclabel,relatime,size=4k,mode=755 0 0 systemd /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,name=systemd 0 0 $ cat /proc/cgroups #subsys_name hierarchy num_cgroups enabled cpuset 0 1 1 cpu 0 1 1 cpuacct 0 1 1 memory 0 1 0 devices 0 1 1 freezer 0 1 1 net_cls 0 1 1 blkio 0 1 1 perf_event 0 1 1 $ cat /proc/$(pidof libvirtd)/cgroup 1:name=systemd:/ I hope this will be enough to fix this issue. Kind regards, Laurent Bigonville [0]http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=721979