In previous versions of CentOS, system administrators built
custom cgroup hierarchies with use of the cgconfig command from the libcgroup
package. This package is now deprecated. There is only special situation,
in which libgroups should be used.

CentOS 7 moves the resource management settings from the
process level to the application level by binding the cgroup hierarchy
with the systemd unit hierarchy. Therefore, you can manage the cgroup tree
with systemctl commands.

For more details see Red Hat Enterprise Linux 7 Resource Management Guide,
Chapter 2 (Using Control Groups):
[link:https://documentation-devel.engineering.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Resource_Management_Guide/ch-Using_Control_Groups.html]
Chapter 3 (Using libcgroup Tools)
[link:https://documentation-devel.engineering.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Resource_Management_Guide/ch-Using_libcgroup_Tools.html]