Understanding resource controllers

There are a few different names for this cgroups feature. I prefer to use the term resource controllers. In other documentation, you may see these resource controllers referred to as either subsystems or just as controllers. All of these terms refer to the same thing, which is the cgroups technology that allows us to control the resource usage of the various running processes. Before we start getting our hands too dirty, let's see what resource controllers we have.

Examining the resource controllers

The best way to see what resource controllers we have is to install some cgroup tools. On the Ubuntu machine, do:

donnie@ubuntu2004:~$ sudo apt install cgroup-tools

On the Alma machine, do:

[donnie@localhost ~]$ sudo dnf install libcgroup-tools

On either machine, we can now use lssubsys to view our active resource controllers, like this:

donnie@ubuntu2004:~$ lssubsys
cpuset
cpu,cpuacct
blkio
memory
devices
freezer
net_cls,net_prio...