Enabling cgroups v2

At boot time, Oracle Linux 8 mounts cgroups v1 by default. To use cgroups v2, you must manually configure the system.

Verify that cgroups v2 is enabled and mounted on the system.
```
sudo mount -l | grep cgroup
```
```
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,seclabel,nsdelegate,memory_recursiveprot)
```
If the output of the command doesn't specify cgroup2, then do the following to enable version 2.
1. Configure the system boot to mount cgroups v2 by default.
```
sudo grubby --update-kernel=/boot/vmlinuz-$(uname -r) --args="systemd.unified_cgroup_hierarchy=1"
```
  The command adds systemd.unified_cgroup_hierarchy=1 to the current boot entry. To add this parameter to all kernel boot entries, type:
```
sudo grubby --update-kernel=ALL --args="systemd.unified_cgroup_hierarchy=1"
```
2. Reboot the system.
3. After the system reboots, verify that cgroups v2 is now mounted.
```
sudo mount -l | grep cgroup
```
Optionally, check the contents of /sys/fs/cgroup directory, which is also called the root control group.
```
ls -l /sys/fs/cgroup/
```
For cgroups v2, the files in the directory should have prefixes to their file names, for example, cgroup.*, cpu.*, memory.*, and so on. See About the Control Group File System.