I have a RHEL6 that hosts many kvm virtual machines. It has been working fine for a couple years. I apply errata updates about once a week. In the last couple weeks, I've ran into a bug where the virtual machines start failing to start with a cgroup error message. If I reboot the host (very disruptive) then things start working normaly for a few days. Can I configure qemu/libvirt not to use cgroups at all as a temporary workaround? How would I do that? Here is example of trying to start a vm (that hasn't been started since boot) after the problem manifests itself. [root@virthost ~]# find /cgroup | grep r04s14 [root@virthost ~]# virsh start r04s14 error: Failed to start domain r04s14 error: Unable to create cgroup for r04s14: No such file or directory [root@virthost ~]# find /cgroup | grep r04s14 /cgroup/cpu/libvirt/qemu/r04s14 /cgroup/cpu/libvirt/qemu/r04s14/cpu.rt_period_us /cgroup/cpu/libvirt/qemu/r04s14/cpu.rt_runtime_us /cgroup/cpu/libvirt/qemu/r04s14/cpu.stat /cgroup/cpu/libvirt/qemu/r04s14/cpu.cfs_period_us /cgroup/cpu/libvirt/qemu/r04s14/cpu.cfs_quota_us /cgroup/cpu/libvirt/qemu/r04s14/cpu.shares /cgroup/cpu/libvirt/qemu/r04s14/cgroup.event_control /cgroup/cpu/libvirt/qemu/r04s14/notify_on_release /cgroup/cpu/libvirt/qemu/r04s14/cgroup.procs /cgroup/cpu/libvirt/qemu/r04s14/tasks /cgroup/cpuacct/libvirt/qemu/r04s14 /cgroup/cpuacct/libvirt/qemu/r04s14/cpuacct.stat /cgroup/cpuacct/libvirt/qemu/r04s14/cpuacct.usage_percpu /cgroup/cpuacct/libvirt/qemu/r04s14/cpuacct.usage /cgroup/cpuacct/libvirt/qemu/r04s14/cgroup.event_control /cgroup/cpuacct/libvirt/qemu/r04s14/notify_on_release /cgroup/cpuacct/libvirt/qemu/r04s14/cgroup.procs /cgroup/cpuacct/libvirt/qemu/r04s14/tasks [root@virthost ~]#