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<refentry id="systemd.cgroup">

<refentryinfo>

<title>systemd.cgroup</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>systemd.cgroup</refentrytitle>

<manvolnum>5</manvolnum>

</refmeta>

<refnamediv>

<refname>systemd.cgroup</refname>

<refpurpose>Cgroup configuration unit settings</refpurpose>

</refnamediv>

<refsynopsisdiv>

<para>

<filename><replaceable>slice</replaceable>.slice</filename>,

<filename><replaceable>scope</replaceable>.scope</filename>,

<filename><replaceable>service</replaceable>.service</filename>,

<filename><replaceable>socket</replaceable>.socket</filename>,

<filename><replaceable>mount</replaceable>.mount</filename>,

<filename><replaceable>swap</replaceable>.swap</filename>

</para>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para>Unit configuration files for services, slices, scopes,

sockets, mount points, and swap devices share a subset of

configuration options which configure the control group settings

for spawned processes.</para>

<para>This man page lists the configuration options shared by

those six unit types. See

<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>

for the common options of all unit configuration files, and

<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

and

<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>

for more information on the specific unit configuration files. The

execution specific configuration options are configured in the

[Slice], [Scope], [Service], [Socket], [Mount], or [Swap]

sections, depending on the unit type.</para>

</refsect1>

<refsect1>

<title>Options</title>

<para>Units of the types listed above can have settings

for cgroup configuration:</para>

<variablelist class='unit-directives'>

<varlistentry>

<term><varname>CPUAccounting=</varname></term>

<listitem>

<para>Turn on the CPU usage accounting for this

unit.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>BlockIOAccounting=</varname></term>

<listitem>

<para>Turn on the Block IO bandwidth accounting

for this unit.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>MemoryAccounting=</varname></term>

<listitem>

<para>Turn on the process and kernel memory

accounting for this unit.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>CPUShares=<replaceable>weight</replaceable></varname></term>

<listitem>

<para>Assign the specified overall CPU time share weight to

the processes executed. Takes an integer value. This

controls the <literal>cpu.shares</literal> control group

attribute, which defaults to 1024. For details about this

control group attribute see <ulink

url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para>

<para>Implies <literal>CPUAccounting=true</literal>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>MemoryLimit=<replaceable>bytes</replaceable></varname></term>

<term><varname>MemorySoftLimit=<replaceable>bytes</replaceable></varname></term>

<listitem>

<para>Specify the hard and soft limits on maximum memory

usage of the executed processes. The "hard" limit specifies

how much process and kernel memory can be used by tasks in

this unit, when there is no memory contention. If the kernel

detects memory contention, memory reclaim will be performed

until the memory usage is within the "soft" limit. Takes a

memory size in bytes. If the value is suffixed with K, M, G

or T the specified memory size is parsed as Kilobytes,

Megabytes, Gigabytes, or Terabytes (with the base 1024),

respectively. This controls the

<literal>memory.limit_in_bytes</literal> and

<literal>memory.soft_limit_in_bytes</literal> control group

attributes. For details about these control group attributes

see <ulink

url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para>

<para>Implies <literal>MemoryAccounting=true</literal>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term>

<listitem><para>Set the default

overall block IO weight for the

executed processes. Takes a single

weight value (between 10 and 1000) to

set the default block IO weight. This

controls the

<literal>blkio.weight</literal>

control group attribute, which

defaults to 1000. For details about

this control group attribute see

<ulink

url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>

</varlistentry>

<varlistentry>

<term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>

<listitem>

<para>Set the per-device overall block IO weight for the

executed processes. Takes a space-separated pair of a file

path and a weight value to specify the device specific

weight value, between 10 and 1000. (Example: "/dev/sda

500"). The file path may be specified as path to a block

device node or as any other file in which case the backing

block device of the file system of the file is

determined. This controls the

<literal>blkio.weight_device</literal> control group

attribute, which defaults to 1000. Use this option multiple

times to set weights for multiple devices. For details about

this control group attribute see <ulink

url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>BlockIOReadBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>

<term><varname>BlockIOWriteBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>

<listitem>

<para>Set the per-device overall block IO bandwidth limit

for the executed processes. Takes a space-separated pair of

a file path and a bandwidth value (in bytes per second) to

specify the device specific bandwidth. The file path may be

a path to a block device node, or as any other file in which

case the backing block device of the file system of the file

is used. If the bandwidth is suffixed with K, M, G, or T

the specified bandwidth is parsed as Kilobytes, Megabytes,

Gigabytes, or Terabytes, respectively (Example:

"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This

controls the <literal>blkio.read_bps_device</literal> and

<literal>blkio.write_bps_device</literal> control group

attributes. Use this option multiple times to set bandwidth

limits for multiple devices. For details about these control

group attributes see

<ulink url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>DeviceAllow=</varname></term>

<listitem>

<para>Control access to specific device nodes by the

executed processes. Takes two space-separated strings: a

device node path (such as <filename>/dev/null</filename>)

followed by a combination of <constant>r</constant>,

<constant>w</constant>, <constant>m</constant> to control

<emphasis>r</emphasis>eading, <emphasis>w</emphasis>riting,

or creating of the specific device node by the unit

(<emphasis>m</emphasis>knod), respectively. This controls

the <literal>devices.allow</literal> and

<literal>devices.deny</literal> control group

attributes. For details about these control group attributes

see <ulink

url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>DevicePolicy=auto|closed|strict</varname></term>

<listitem>

<para>

Control the policy for allowing device access:

</para>

<variablelist>

<varlistentry>

<term><option>strict</option></term>

<listitem>

<para>means to only allow types of access that are

explicitly specified.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><option>closed</option></term>

<listitem>

<para>in addition allows access to standard pseudo

devices including

<filename>/dev/null</filename>,

<filename>/dev/zero</filename>,

<filename>/dev/full</filename>,

<filename>/dev/random</filename>, and

<filename>/dev/urandom</filename>.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><option>auto</option></term>

<listitem>

<para>

in addition allows access to all devices if no

explicit <varname>DeviceAllow=</varname> is present.

This is the default.

</para>

</listitem>

</varlistentry>

</variablelist>

</listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

The documentation for control groups and specific controllers in the Linux kernel:

<ulink url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>,

<ulink url="http://www.kernel.org/doc/Documentation/cgroups/cpuacct.txt">cpuacct.txt</ulink>,

<ulink url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>,

<ulink url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.

</para>

</refsect1>

</refentry>