[libvirt] cgroups issues when logind is running without systemd acting as init system

[Laurent Bigonville]

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