man/systemd-sysctl.service.xml

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   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!--
   5   SPDX-License-Identifier: LGPL-2.1+
   6
   7   This file is part of systemd.
   8
   9   Copyright 2012 Lennart Poettering
  10 -->
  11 <refentry id="systemd-sysctl.service"
  12     xmlns:xi="http://www.w3.org/2001/XInclude">
  13
  14   <refentryinfo>
  15     <title>systemd-sysctl.service</title>
  16     <productname>systemd</productname>
  17
  18     <authorgroup>
  19       <author>
  20         <contrib>Developer</contrib>
  21         <firstname>Lennart</firstname>
  22         <surname>Poettering</surname>
  23         <email>lennart@poettering.net</email>
  24       </author>
  25     </authorgroup>
  26   </refentryinfo>
  27
  28   <refmeta>
  29     <refentrytitle>systemd-sysctl.service</refentrytitle>
  30     <manvolnum>8</manvolnum>
  31   </refmeta>
  32
  33   <refnamediv>
  34     <refname>systemd-sysctl.service</refname>
  35     <refname>systemd-sysctl</refname>
  36     <refpurpose>Configure kernel parameters at boot</refpurpose>
  37   </refnamediv>
  38
  39   <refsynopsisdiv>
  40     <cmdsynopsis>
  41       <command>/usr/lib/systemd/systemd-sysctl</command>
  42       <arg choice="opt" rep="repeat">OPTIONS</arg>
  43       <arg choice="opt" rep="repeat"><replaceable>CONFIGFILE</replaceable></arg>
  44     </cmdsynopsis>
  45     <para><filename>systemd-sysctl.service</filename></para>
  46   </refsynopsisdiv>
  47
  48   <refsect1>
  49     <title>Description</title>
  50
  51     <para><filename>systemd-sysctl.service</filename> is an early boot
  52     service that configures
  53     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  54     kernel parameters by invoking <command>/usr/lib/systemd/systemd-sysctl</command>.</para>
  55
  56     <para>When invoked with no arguments, <command>/usr/lib/systemd/systemd-sysctl</command> applies
  57     all directives from configuration files listed in
  58     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  59     If one or more filenames are passed on the command line, only the directives in these files are
  60     applied.</para>
  61
  62     <para>In addition, <option>--prefix=</option> option may be used to limit which sysctl
  63     settings are applied.</para>
  64
  65     <para>See
  66     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  67     for information about the configuration of sysctl settings. After sysctl configuration is
  68     changed on disk, it must be written to the files in <filename>/proc/sys</filename> before it
  69     takes effect. It is possible to update specific settings, or simply to reload all configuration,
  70     see Examples below.</para>
  71   </refsect1>
  72
  73   <refsect1><title>Options</title>
  74     <variablelist>
  75       <varlistentry id='prefix'>
  76         <term><option>--prefix=</option></term>
  77         <listitem>
  78           <para>Only apply rules with the specified prefix.</para>
  79         </listitem>
  80       </varlistentry>
  81
  82       <xi:include href="standard-options.xml" xpointer="help" />
  83       <xi:include href="standard-options.xml" xpointer="version" />
  84
  85     </variablelist>
  86   </refsect1>
  87
  88   <refsect1>
  89     <title>Examples</title>
  90
  91     <example>
  92       <title>Reset all sysctl settings</title>
  93
  94       <programlisting>systemctl restart systemd-sysctl</programlisting>
  95     </example>
  96
  97     <example>
  98       <title>View coredump handler configuration</title>
  99
 100       <programlisting># sysctl kernel.core_pattern
 101 kernel.core_pattern = |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I
 102 </programlisting>
 103     </example>
 104
 105     <example>
 106       <title>Update coredump handler configuration</title>
 107
 108       <programlisting># /usr/lib/systemd/systemd-sysctl --prefix kernel.core_pattern</programlisting>
 109
 110       <para>This searches all the directories listed in
 111       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 112       for configuration files and writes <filename>/proc/sys/kernel/core_pattern</filename>.</para>
 113     </example>
 114
 115     <example>
 116       <title>Update coredump handler configuration according to a specific file</title>
 117
 118       <programlisting># /usr/lib/systemd/systemd-sysctl 50-coredump.conf</programlisting>
 119
 120       <para>This applies all the settings found in <filename>50-coredump.conf</filename>.
 121       Either <filename>/etc/sysctl.d/50-coredump.conf</filename>, or
 122       <filename>/run/sysctl.d/50-coredump.conf</filename>, or
 123       <filename>/usr/lib/sysctl.d/50-coredump.conf</filename> will be used, in the order
 124       of preference.</para>
 125     </example>
 126
 127     <para>See
 128     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 129     for various ways to directly apply sysctl settings.</para>
 130   </refsect1>
 131
 132   <refsect1>
 133     <title>See Also</title>
 134     <para>
 135       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 136       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 137       <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 138     </para>
 139   </refsect1>
 140
 141 </refentry>