---
title: Control Group APIs and Delegation
+category: Interfaces
+layout: default
---
# Control Group APIs and Delegation
poor implementations of the components interfacing with systemd of current
container managers.
-Before you read on, please make sure you read the low-level [kernel
-documentation about
-cgroup v2](https://www.kernel.org/doc/Documentation/cgroup-v2.txt). This
-documentation then adds in the higher-level view from systemd.
+Before you read on, please make sure you read the low-level kernel
+documentation about the
+[unified cgroup hierarchy](https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html).
+This document then adds in the higher-level view from systemd.
This document augments the existing documentation we already have:
In unit files the `Delegate=` property is superficially exposed as
boolean. However, since v236 it optionally takes a list of controller names
instead. If so, delegation is requested for listed controllers
-specifically. Note hat this only encodes a request. Depending on various
+specifically. Note that this only encodes a request. Depending on various
parameters it might happen that your service actually will get fewer
controllers delegated (for example, because the controller is not available on
the current kernel or was turned off) or more. If no list is specified