man/systemd-sysctl.service.xml

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