Bug#959022: Works with kernel options

[Thomas Goirand <zigo@debian.org>]

Hi,

With this as kernel boot options:

systemd.unified_cgroup_hierarchy=false
systemd.legacy_systemd_cgroup_controller=false

I have the old "cgcreate -g blkio:cinder-copy" that works perfectly, as
the old cgroups v1 get mounted in the sysfs:

# mount | grep -i cgroup
cgroup2 on /sys/fs/cgroup/unified type cgroup2
cgroup on /sys/fs/cgroup/systemd type cgroup
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup
cgroup on /sys/fs/cgroup/cpuset type cgroup
cgroup on /sys/fs/cgroup/hugetlb type cgroup
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup
cgroup on /sys/fs/cgroup/devices type cgroup
cgroup on /sys/fs/cgroup/blkio type cgroup
cgroup on /sys/fs/cgroup/freezer type cgroup
cgroup on /sys/fs/cgroup/perf_event type cgroup
cgroup on /sys/fs/cgroup/pids type cgroup
cgroup on /sys/fs/cgroup/memory type cgroup
cgroup on /sys/fs/cgroup/rdma type cgroup

So I see no reason to remove cgroup-tools, which would otherwise break
Cinder QoS for I/O.

Cheers,

Thomas Goirand (zigo)