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768 lines
41 KiB
XML
768 lines
41 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2013 Zbigniew Jędrzejewski-Szmek
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="systemd.resource-control">
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<refentryinfo>
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<title>systemd.resource-control</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd.resource-control</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.resource-control</refname>
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<refpurpose>Resource control unit settings</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para>
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<filename><replaceable>slice</replaceable>.slice</filename>,
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<filename><replaceable>scope</replaceable>.scope</filename>,
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<filename><replaceable>service</replaceable>.service</filename>,
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<filename><replaceable>socket</replaceable>.socket</filename>,
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<filename><replaceable>mount</replaceable>.mount</filename>,
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<filename><replaceable>swap</replaceable>.swap</filename>
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</para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>Unit configuration files for services, slices, scopes, sockets, mount points, and swap devices share a subset
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of configuration options for resource control of spawned processes. Internally, this relies on the Linux Control
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Groups (cgroups) kernel concept for organizing processes in a hierarchical tree of named groups for the purpose of
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resource management.</para>
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<para>This man page lists the configuration options shared by
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those six unit types. See
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for the common options of all unit configuration files, and
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<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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and
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<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for more information on the specific unit configuration files. The
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resource control configuration options are configured in the
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[Slice], [Scope], [Service], [Socket], [Mount], or [Swap]
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sections, depending on the unit type.</para>
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<para>In addition, options which control resources available to programs
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<emphasis>executed</emphasis> by systemd are listed in
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<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
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Those options complement options listed here.</para>
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<para>See the <ulink
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url="https://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
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Control Group Interfaces</ulink> for an introduction on how to make
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use of resource control APIs from programs.</para>
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</refsect1>
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<refsect1>
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<title>Automatic Dependencies</title>
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<para>Units with the <varname>Slice=</varname> setting set automatically acquire <varname>Requires=</varname> and
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<varname>After=</varname> dependencies on the specified slice unit.</para>
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</refsect1>
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<refsect1>
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<title>Unified and Legacy Control Group Hierarchies</title>
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<para>The unified control group hierarchy is the new version of kernel control group interface, see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>. Depending on the resource type,
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there are differences in resource control capabilities. Also, because of interface changes, some resource types
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have separate set of options on the unified hierarchy.</para>
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<para>
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<variablelist>
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<varlistentry>
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<term><option>CPU</option></term>
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<listitem>
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<para>Due to the lack of consensus in the kernel community, the CPU controller support on the unified
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control group hierarchy requires out-of-tree kernel patches. See <ulink
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url="https://git.kernel.org/cgit/linux/kernel/git/tj/cgroup.git/tree/Documentation/cgroup-v2-cpu.txt?h=cgroup-v2-cpu">cgroup-v2-cpu.txt</ulink>.</para>
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<para><varname>CPUWeight=</varname> and <varname>StartupCPUWeight=</varname> replace
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<varname>CPUShares=</varname> and <varname>StartupCPUShares=</varname>, respectively.</para>
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<para>The <literal>cpuacct</literal> controller does not exist separately on the unified hierarchy.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>Memory</option></term>
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<listitem>
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<para><varname>MemoryMax=</varname> replaces <varname>MemoryLimit=</varname>. <varname>MemoryLow=</varname>
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and <varname>MemoryHigh=</varname> are effective only on unified hierarchy.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>IO</option></term>
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<listitem>
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<para><varname>IO</varname> prefixed settings are superset of and replace <varname>BlockIO</varname>
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prefixed ones. On unified hierarchy, IO resource control also applies to buffered writes.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>To ease the transition, there is best-effort translation between the two versions of settings. For each
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controller, if any of the settings for the unified hierarchy are present, all settings for the legacy hierarchy are
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ignored. If the resulting settings are for the other type of hierarchy, the configurations are translated before
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application.</para>
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<para>Legacy control group hierarchy (see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>), also called cgroup-v1,
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doesn't allow safe delegation of controllers to unprivileged processes. If the system uses the legacy control group
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hierarchy, resource control is disabled for systemd user instance, see
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
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</para>
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</refsect1>
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<refsect1>
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<title>Options</title>
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<para>Units of the types listed above can have settings
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for resource control configuration:</para>
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<variablelist class='unit-directives'>
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<varlistentry>
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<term><varname>CPUAccounting=</varname></term>
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<listitem>
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<para>Turn on CPU usage accounting for this unit. Takes a
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boolean argument. Note that turning on CPU accounting for
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one unit will also implicitly turn it on for all units
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contained in the same slice and for all its parent slices
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and the units contained therein. The system default for this
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setting may be controlled with
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<varname>DefaultCPUAccounting=</varname> in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>CPUWeight=<replaceable>weight</replaceable></varname></term>
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<term><varname>StartupCPUWeight=<replaceable>weight</replaceable></varname></term>
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<listitem>
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<para>Assign the specified CPU time weight to the processes executed, if the unified control group hierarchy
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is used on the system. These options take an integer value and control the <literal>cpu.weight</literal>
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control group attribute. The allowed range is 1 to 10000. Defaults to 100. For details about this control
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group attribute, see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink> and <ulink
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url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.
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The available CPU time is split up among all units within one slice relative to their CPU time weight.</para>
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<para>While <varname>StartupCPUWeight=</varname> only applies to the startup phase of the system,
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<varname>CPUWeight=</varname> applies to normal runtime of the system, and if the former is not set also to
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the startup phase. Using <varname>StartupCPUWeight=</varname> allows prioritizing specific services at
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boot-up differently than during normal runtime.</para>
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<para>Implies <literal>CPUAccounting=true</literal>.</para>
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<para>These settings replace <varname>CPUShares=</varname> and <varname>StartupCPUShares=</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>CPUQuota=</varname></term>
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<listitem>
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<para>Assign the specified CPU time quota to the processes executed. Takes a percentage value, suffixed with
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"%". The percentage specifies how much CPU time the unit shall get at maximum, relative to the total CPU time
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available on one CPU. Use values > 100% for allotting CPU time on more than one CPU. This controls the
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<literal>cpu.max</literal> attribute on the unified control group hierarchy and
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<literal>cpu.cfs_quota_us</literal> on legacy. For details about these control group attributes, see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink> and <ulink
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url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para>
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<para>Example: <varname>CPUQuota=20%</varname> ensures that the executed processes will never get more than
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20% CPU time on one CPU.</para>
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<para>Implies <literal>CPUAccounting=true</literal>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MemoryAccounting=</varname></term>
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<listitem>
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<para>Turn on process and kernel memory accounting for this
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unit. Takes a boolean argument. Note that turning on memory
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accounting for one unit will also implicitly turn it on for
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all units contained in the same slice and for all its parent
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slices and the units contained therein. The system default
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for this setting may be controlled with
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<varname>DefaultMemoryAccounting=</varname> in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MemoryLow=<replaceable>bytes</replaceable></varname></term>
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<listitem>
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<para>Specify the best-effort memory usage protection of the executed processes in this unit. If the memory
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usages of this unit and all its ancestors are below their low boundaries, this unit's memory won't be
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reclaimed as long as memory can be reclaimed from unprotected units.</para>
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<para>Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is
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parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a
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percentage value may be specified, which is taken relative to the installed physical memory on the
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system. This controls the <literal>memory.low</literal> control group attribute. For details about this
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control group attribute, see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
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<para>Implies <literal>MemoryAccounting=true</literal>.</para>
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<para>This setting is supported only if the unified control group hierarchy is used and disables
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<varname>MemoryLimit=</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MemoryHigh=<replaceable>bytes</replaceable></varname></term>
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<listitem>
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<para>Specify the high limit on memory usage of the executed processes in this unit. Memory usage may go
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above the limit if unavoidable, but the processes are heavily slowed down and memory is taken away
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aggressively in such cases. This is the main mechanism to control memory usage of a unit.</para>
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<para>Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is
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parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a
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percentage value may be specified, which is taken relative to the installed physical memory on the
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system. If assigned the
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special value <literal>infinity</literal>, no memory limit is applied. This controls the
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<literal>memory.high</literal> control group attribute. For details about this control group attribute, see
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<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
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<para>Implies <literal>MemoryAccounting=true</literal>.</para>
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<para>This setting is supported only if the unified control group hierarchy is used and disables
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<varname>MemoryLimit=</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MemoryMax=<replaceable>bytes</replaceable></varname></term>
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<listitem>
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<para>Specify the absolute limit on memory usage of the executed processes in this unit. If memory usage
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cannot be contained under the limit, out-of-memory killer is invoked inside the unit. It is recommended to
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use <varname>MemoryHigh=</varname> as the main control mechanism and use <varname>MemoryMax=</varname> as the
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last line of defense.</para>
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<para>Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is
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parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a
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percentage value may be specified, which is taken relative to the installed physical memory on the system. If
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assigned the special value <literal>infinity</literal>, no memory limit is applied. This controls the
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<literal>memory.max</literal> control group attribute. For details about this control group attribute, see
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<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
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<para>Implies <literal>MemoryAccounting=true</literal>.</para>
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<para>This setting replaces <varname>MemoryLimit=</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MemorySwapMax=<replaceable>bytes</replaceable></varname></term>
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<listitem>
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<para>Specify the absolute limit on swap usage of the executed processes in this unit.</para>
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<para>Takes a swap size in bytes. If the value is suffixed with K, M, G or T, the specified swap size is
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parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If assigned the
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special value <literal>infinity</literal>, no swap limit is applied. This controls the
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<literal>memory.swap.max</literal> control group attribute. For details about this control group attribute,
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see <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
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<para>Implies <literal>MemoryAccounting=true</literal>.</para>
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<para>This setting is supported only if the unified control group hierarchy is used and disables
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<varname>MemoryLimit=</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>TasksAccounting=</varname></term>
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<listitem>
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<para>Turn on task accounting for this unit. Takes a
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boolean argument. If enabled, the system manager will keep
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track of the number of tasks in the unit. The number of
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tasks accounted this way includes both kernel threads and
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userspace processes, with each thread counting
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individually. Note that turning on tasks accounting for one
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unit will also implicitly turn it on for all units contained
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in the same slice and for all its parent slices and the
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units contained therein. The system default for this setting
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may be controlled with
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<varname>DefaultTasksAccounting=</varname> in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>TasksMax=<replaceable>N</replaceable></varname></term>
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<listitem>
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<para>Specify the maximum number of tasks that may be created in the unit. This ensures that the number of
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tasks accounted for the unit (see above) stays below a specific limit. This either takes an absolute number
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of tasks or a percentage value that is taken relative to the configured maximum number of tasks on the
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system. If assigned the special value <literal>infinity</literal>, no tasks limit is applied. This controls
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the <literal>pids.max</literal> control group attribute. For details about this control group attribute, see
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<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/pids.txt">pids.txt</ulink>.</para>
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<para>Implies <literal>TasksAccounting=true</literal>. The
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system default for this setting may be controlled with
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<varname>DefaultTasksMax=</varname> in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>IOAccounting=</varname></term>
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<listitem>
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<para>Turn on Block I/O accounting for this unit, if the unified control group hierarchy is used on the
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system. Takes a boolean argument. Note that turning on block I/O accounting for one unit will also implicitly
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turn it on for all units contained in the same slice and all for its parent slices and the units contained
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therein. The system default for this setting may be controlled with <varname>DefaultIOAccounting=</varname>
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in
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<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
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<para>This setting replaces <varname>BlockIOAccounting=</varname> and disables settings prefixed with
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<varname>BlockIO</varname> or <varname>StartupBlockIO</varname>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>IOWeight=<replaceable>weight</replaceable></varname></term>
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<term><varname>StartupIOWeight=<replaceable>weight</replaceable></varname></term>
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<listitem>
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<para>Set the default overall block I/O weight for the executed processes, if the unified control group
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hierarchy is used on the system. Takes a single weight value (between 1 and 10000) to set the default block
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I/O weight. This controls the <literal>io.weight</literal> control group attribute, which defaults to
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100. For details about this control group attribute, see <ulink
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url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>. The available I/O
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bandwidth is split up among all units within one slice relative to their block I/O weight.</para>
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<para>While <varname>StartupIOWeight=</varname> only applies
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to the startup phase of the system,
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<varname>IOWeight=</varname> applies to the later runtime of
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the system, and if the former is not set also to the startup
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phase. This allows prioritizing specific services at boot-up
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|
differently than during runtime.</para>
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<para>Implies <literal>IOAccounting=true</literal>.</para>
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<para>These settings replace <varname>BlockIOWeight=</varname> and <varname>StartupBlockIOWeight=</varname>
|
|
and disable settings prefixed with <varname>BlockIO</varname> or <varname>StartupBlockIO</varname>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Set the per-device overall block I/O weight for the executed processes, if the unified control group
|
|
hierarchy is used on the system. Takes a space-separated pair of a file path and a weight value to specify
|
|
the device specific weight value, between 1 and 10000. (Example: "/dev/sda 1000"). 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>io.weight</literal> control group
|
|
attribute, which defaults to 100. Use this option multiple times to set weights for multiple devices. For
|
|
details about this control group attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
|
|
|
|
<para>Implies <literal>IOAccounting=true</literal>.</para>
|
|
|
|
<para>This setting replaces <varname>BlockIODeviceWeight=</varname> and disables settings prefixed with
|
|
<varname>BlockIO</varname> or <varname>StartupBlockIO</varname>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IOReadBandwidthMax=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
|
|
<term><varname>IOWriteBandwidthMax=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Set the per-device overall block I/O bandwidth maximum limit for the executed processes, if the unified
|
|
control group hierarchy is used on the system. This limit is not work-conserving and the executed processes
|
|
are not allowed to use more even if the device has idle capacity. 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, to the base of 1000. (Example:
|
|
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This controls the <literal>io.max</literal> control
|
|
group attributes. Use this option multiple times to set bandwidth limits for multiple devices. For details
|
|
about this control group attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.
|
|
</para>
|
|
|
|
<para>Implies <literal>IOAccounting=true</literal>.</para>
|
|
|
|
<para>These settings replace <varname>BlockIOReadBandwidth=</varname> and
|
|
<varname>BlockIOWriteBandwidth=</varname> and disable settings prefixed with <varname>BlockIO</varname> or
|
|
<varname>StartupBlockIO</varname>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IOReadIOPSMax=<replaceable>device</replaceable> <replaceable>IOPS</replaceable></varname></term>
|
|
<term><varname>IOWriteIOPSMax=<replaceable>device</replaceable> <replaceable>IOPS</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Set the per-device overall block I/O IOs-Per-Second maximum limit for the executed processes, if the
|
|
unified control group hierarchy is used on the system. This limit is not work-conserving and the executed
|
|
processes are not allowed to use more even if the device has idle capacity. Takes a space-separated pair of
|
|
a file path and an IOPS value to specify the device specific IOPS. 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 IOPS is suffixed with K, M, G, or T, the specified IOPS is parsed as KiloIOPS, MegaIOPS,
|
|
GigaIOPS, or TeraIOPS, respectively, to the base of 1000. (Example:
|
|
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 1K"). This controls the <literal>io.max</literal> control
|
|
group attributes. Use this option multiple times to set IOPS limits for multiple devices. For details about
|
|
this control group attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.
|
|
</para>
|
|
|
|
<para>Implies <literal>IOAccounting=true</literal>.</para>
|
|
|
|
<para>These settings are supported only if the unified control group hierarchy is used and disable settings
|
|
prefixed with <varname>BlockIO</varname> or <varname>StartupBlockIO</varname>.</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 specifier 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 creation of the specific device node(s) 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="https://www.kernel.org/doc/Documentation/cgroup-v1/devices.txt">devices.txt</ulink>.</para>
|
|
|
|
<para>The device node specifier is either a path to a device
|
|
node in the file system, starting with
|
|
<filename>/dev/</filename>, or a string starting with either
|
|
<literal>char-</literal> or <literal>block-</literal>
|
|
followed by a device group name, as listed in
|
|
<filename>/proc/devices</filename>. The latter is useful to
|
|
whitelist all current and future devices belonging to a
|
|
specific device group at once. The device group is matched
|
|
according to file name globbing rules, you may hence use the
|
|
<literal>*</literal> and <literal>?</literal>
|
|
wildcards. Examples: <filename>/dev/sda5</filename> is a
|
|
path to a device node, referring to an ATA or SCSI block
|
|
device. <literal>char-pts</literal> and
|
|
<literal>char-alsa</literal> are specifiers for all pseudo
|
|
TTYs and all ALSA sound devices,
|
|
respectively. <literal>char-cpu/*</literal> is a specifier
|
|
matching all CPU related device groups.</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>
|
|
|
|
<varlistentry>
|
|
<term><varname>Slice=</varname></term>
|
|
|
|
<listitem>
|
|
<para>The name of the slice unit to place the unit
|
|
in. Defaults to <filename>system.slice</filename> for all
|
|
non-instantiated units of all unit types (except for slice
|
|
units themselves see below). Instance units are by default
|
|
placed in a subslice of <filename>system.slice</filename>
|
|
that is named after the template name.</para>
|
|
|
|
<para>This option may be used to arrange systemd units in a
|
|
hierarchy of slices each of which might have resource
|
|
settings applied.</para>
|
|
|
|
<para>For units of type slice, the only accepted value for
|
|
this setting is the parent slice. Since the name of a slice
|
|
unit implies the parent slice, it is hence redundant to ever
|
|
set this parameter directly for slice units.</para>
|
|
|
|
<para>Special care should be taken when relying on the default slice assignment in templated service units
|
|
that have <varname>DefaultDependencies=no</varname> set, see
|
|
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, section
|
|
"Automatic Dependencies" for details.</para>
|
|
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Delegate=</varname></term>
|
|
|
|
<listitem>
|
|
<para>Turns on delegation of further resource control
|
|
partitioning to processes of the unit. For unprivileged
|
|
services (i.e. those using the <varname>User=</varname>
|
|
setting), this allows processes to create a subhierarchy
|
|
beneath its control group path. For privileged services and
|
|
scopes, this ensures the processes will have all control
|
|
group controllers enabled.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Deprecated Options</title>
|
|
|
|
<para>The following options are deprecated. Use the indicated superseding options instead:</para>
|
|
|
|
<variablelist class='unit-directives'>
|
|
|
|
<varlistentry>
|
|
<term><varname>CPUShares=<replaceable>weight</replaceable></varname></term>
|
|
<term><varname>StartupCPUShares=<replaceable>weight</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Assign the specified CPU time share weight to the processes executed. These options take an integer
|
|
value and control the <literal>cpu.shares</literal> control group attribute. The allowed range is 2 to
|
|
262144. Defaults to 1024. For details about this control group attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.
|
|
The available CPU time is split up among all units within one slice relative to their CPU time share
|
|
weight.</para>
|
|
|
|
<para>While <varname>StartupCPUShares=</varname> only applies to the startup phase of the system,
|
|
<varname>CPUShares=</varname> applies to normal runtime of the system, and if the former is not set also to
|
|
the startup phase. Using <varname>StartupCPUShares=</varname> allows prioritizing specific services at
|
|
boot-up differently than during normal runtime.</para>
|
|
|
|
<para>Implies <literal>CPUAccounting=true</literal>.</para>
|
|
|
|
<para>These settings are deprecated. Use <varname>CPUWeight=</varname> and
|
|
<varname>StartupCPUWeight=</varname> instead.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>MemoryLimit=<replaceable>bytes</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Specify the limit on maximum memory usage of the executed processes. The limit specifies how much
|
|
process and kernel memory can be used by tasks in this unit. 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. Alternatively, a percentage value may be specified, which is
|
|
taken relative to the installed physical memory on the system. If assigned the special value
|
|
<literal>infinity</literal>, no memory limit is applied. This controls the
|
|
<literal>memory.limit_in_bytes</literal> control group attribute. For details about this control group
|
|
attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt">memory.txt</ulink>.</para>
|
|
|
|
<para>Implies <literal>MemoryAccounting=true</literal>.</para>
|
|
|
|
<para>This setting is deprecated. Use <varname>MemoryMax=</varname> instead.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>BlockIOAccounting=</varname></term>
|
|
|
|
<listitem>
|
|
<para>Turn on Block I/O accounting for this unit, if the legacy control group hierarchy is used on the
|
|
system. Takes a boolean argument. Note that turning on block I/O accounting for one unit will also implicitly
|
|
turn it on for all units contained in the same slice and all for its parent slices and the units contained
|
|
therein. The system default for this setting may be controlled with
|
|
<varname>DefaultBlockIOAccounting=</varname> in
|
|
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
|
|
|
|
<para>This setting is deprecated. Use <varname>IOAccounting=</varname> instead.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term>
|
|
<term><varname>StartupBlockIOWeight=<replaceable>weight</replaceable></varname></term>
|
|
|
|
<listitem><para>Set the default overall block I/O weight for the executed processes, if the legacy control
|
|
group hierarchy is used on the system. Takes a single weight value (between 10 and 1000) to set the default
|
|
block I/O weight. This controls the <literal>blkio.weight</literal> control group attribute, which defaults to
|
|
500. For details about this control group attribute, see <ulink
|
|
url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
|
|
The available I/O bandwidth is split up among all units within one slice relative to their block I/O
|
|
weight.</para>
|
|
|
|
<para>While <varname>StartupBlockIOWeight=</varname> only
|
|
applies to the startup phase of the system,
|
|
<varname>BlockIOWeight=</varname> applies to the later runtime
|
|
of the system, and if the former is not set also to the
|
|
startup phase. This allows prioritizing specific services at
|
|
boot-up differently than during runtime.</para>
|
|
|
|
<para>Implies
|
|
<literal>BlockIOAccounting=true</literal>.</para>
|
|
|
|
<para>These settings are deprecated. Use <varname>IOWeight=</varname> and <varname>StartupIOWeight=</varname>
|
|
instead.</para>
|
|
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>
|
|
|
|
<listitem>
|
|
<para>Set the per-device overall block I/O weight for the executed processes, if the legacy control group
|
|
hierarchy is used on the system. 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="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.</para>
|
|
|
|
<para>Implies
|
|
<literal>BlockIOAccounting=true</literal>.</para>
|
|
|
|
<para>This setting is deprecated. Use <varname>IODeviceWeight=</varname> instead.</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 I/O bandwidth limit for the executed processes, if the legacy control
|
|
group hierarchy is used on the system. 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, to the base of 1000. (Example:
|
|
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This controls the
|
|
<literal>blkio.throttle.read_bps_device</literal> and <literal>blkio.throttle.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="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
|
|
</para>
|
|
|
|
<para>Implies
|
|
<literal>BlockIOAccounting=true</literal>.</para>
|
|
|
|
<para>These settings are deprecated. Use <varname>IOReadBandwidthMax=</varname> and
|
|
<varname>IOWriteBandwidthMax=</varname> instead.</para>
|
|
</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.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
|
The documentation for control groups and specific controllers in the Linux kernel:
|
|
<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>,
|
|
<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/cpuacct.txt">cpuacct.txt</ulink>,
|
|
<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt">memory.txt</ulink>,
|
|
<ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
|
|
</para>
|
|
</refsect1>
|
|
</refentry>
|