2.3. Attaching Subsystems to, and Detaching Them from, an Existing Hierarchy

To add a subsystem to an existing hierarchy, detach it from an existing hierarchy, or move it to a different hierarchy, edit the mount section of the /etc/cgconfig.conf file as root, using the same syntax described in Section 2.2, “Creating a Hierarchy and Attaching Subsystems”. When cgconfig next starts, it will reorganize the subsystems according to the hierarchies that you specify.

To add an unattached subsystem to an existing hierarchy, remount the hierarchy. Include the extra subsystem in the mount command, together with the remount option.

~]# lssubsys -am
cpu,cpuset,memory /cgroup/cpu_and_mem
net_cls
ns
cpuacct
devices
freezer
blkio

~]# mount -t cgroup -o remount,cpu,cpuset,cpuacct,memory cpu_and_mem /cgroup/cpu_and_mem

~]# lssubsys -am
cpu,cpuacct,cpuset,memory /cgroup/cpu_and_mem
net_cls
ns
devices
freezer
blkio

Analogously, you can detach a subsystem from an existing hierarchy by remounting the hierarchy and omitting the subsystem name from the -o options. For example, to then detach the cpuacct subsystem, simply remount and omit it:

~]# mount -t cgroup -o remount,cpu,cpuset,memory cpu_and_mem /cgroup/cpu_and_mem