1.4. Additional Resources

To find more information about resource control under systemd, the unit hierarchy, as well as the kernel resource controllers, see the materials listed below:

Installed Documentation

Cgroup-Related Systemd Documentation

The following manual pages contain general information on unified cgroup hierarchy under systemd:
  • systemd.resource-control(5) — describes the configuration options for resource control shared by system units.
  • systemd.unit(5) — describes common options of all unit configuration files.
  • systemd.slice(5) — provides general information about .slice units.
  • systemd.scope(5) — provides general information about .scope units.
  • systemd.service(5) — provides general information about .service units.

Controller-Specific Kernel Documentation

The kernel-doc package provides a detailed documentation of all resource controllers. This package is included in the Optional subscription channel. Before subscribing to the Optional channel, see the Scope of Coverage Details for Optional software, then follow the steps documented in the article called How to access Optional and Supplementary channels, and -devel packages using Red Hat Subscription Manager (RHSM)? on Red Hat Customer Portal. To install kernel-doc from the Optional channel, type as root:
~]# yum install kernel-doc
After the installation, the following files will appear under the /usr/share/doc/kernel-doc-<kernel_version>/Documentation/cgroups/ directory:
  • blkio subsystem — blkio-controller.txt
  • cpuacct subsystem — cpuacct.txt
  • cpuset subsystem — cpusets.txt
  • devices subsystem — devices.txt
  • freezer subsystem — freezer-subsystem.txt
  • memory subsystem — memory.txt
  • net_cls subsystem — net_cls.txt
Additionally, see the following files on further information about the cpu subsystem:
  • Real-Time scheduling — /usr/share/doc/kernel-doc-<kernel_version>/Documentation/scheduler/sched-rt-group.txt
  • CFS scheduling — /usr/share/doc/kernel-doc-<kernel_version>/Documentation/scheduler/sched-bwc.txt

Online Documentation

  • Red Hat Enterprise Linux 7 System Administrator's Guide — The System Administrator's Guide documents relevant information regarding the deployment, configuration, and administration of Red Hat Enterprise Linux 7. This guide contains a detailed explanation of the systemd concepts as well as instructions for service management with systemd.
  • The D-Bus API of systemd — The reference material for D-Bus API commands used to interact with systemd.