man/systemd-sysctl.service.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   4   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   5 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   6 <refentry id="systemd-sysctl.service"
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-sysctl.service</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-sysctl.service</refentrytitle>
  16     <manvolnum>8</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-sysctl.service</refname>
  21     <refname>systemd-sysctl</refname>
  22     <refpurpose>Configure kernel parameters at boot</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <cmdsynopsis>
  27       <command>/usr/lib/systemd/systemd-sysctl</command>
  28       <arg choice="opt" rep="repeat">OPTIONS</arg>
  29       <arg choice="opt" rep="repeat"><replaceable>CONFIGFILE</replaceable></arg>
  30     </cmdsynopsis>
  31     <para><filename>systemd-sysctl.service</filename></para>
  32   </refsynopsisdiv>
  33
  34   <refsect1>
  35     <title>Description</title>
  36
  37     <para><filename>systemd-sysctl.service</filename> is an early boot
  38     service that configures
  39     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  40     kernel parameters by invoking <command>/usr/lib/systemd/systemd-sysctl</command>.</para>
  41
  42     <para>When invoked with no arguments, <command>/usr/lib/systemd/systemd-sysctl</command> applies
  43     all directives from configuration files listed in
  44     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  45     If one or more filenames are passed on the command line, only the directives in these files are
  46     applied.</para>
  47
  48     <para>In addition, <option>--prefix=</option> option may be used to limit which sysctl
  49     settings are applied.</para>
  50
  51     <para>See
  52     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  53     for information about the configuration of sysctl settings. After sysctl configuration is
  54     changed on disk, it must be written to the files in <filename>/proc/sys</filename> before it
  55     takes effect. It is possible to update specific settings, or simply to reload all configuration,
  56     see Examples below.</para>
  57   </refsect1>
  58
  59   <refsect1><title>Options</title>
  60     <variablelist>
  61       <varlistentry id='prefix'>
  62         <term><option>--prefix=</option></term>
  63         <listitem>
  64           <para>Only apply rules with the specified prefix.</para>
  65         </listitem>
  66       </varlistentry>
  67
  68       <xi:include href="standard-options.xml" xpointer="cat-config" />
  69       <xi:include href="standard-options.xml" xpointer="no-pager" />
  70       <xi:include href="standard-options.xml" xpointer="help" />
  71       <xi:include href="standard-options.xml" xpointer="version" />
  72
  73     </variablelist>
  74   </refsect1>
  75
  76   <refsect1>
  77     <title>Examples</title>
  78
  79     <example>
  80       <title>Reset all sysctl settings</title>
  81
  82       <programlisting>systemctl restart systemd-sysctl</programlisting>
  83     </example>
  84
  85     <example>
  86       <title>View coredump handler configuration</title>
  87
  88       <programlisting># sysctl kernel.core_pattern
  89 kernel.core_pattern = |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I
  90 </programlisting>
  91     </example>
  92
  93     <example>
  94       <title>Update coredump handler configuration</title>
  95
  96       <programlisting># /usr/lib/systemd/systemd-sysctl --prefix kernel.core_pattern</programlisting>
  97
  98       <para>This searches all the directories listed in
  99       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 100       for configuration files and writes <filename>/proc/sys/kernel/core_pattern</filename>.</para>
 101     </example>
 102
 103     <example>
 104       <title>Update coredump handler configuration according to a specific file</title>
 105
 106       <programlisting># /usr/lib/systemd/systemd-sysctl 50-coredump.conf</programlisting>
 107
 108       <para>This applies all the settings found in <filename>50-coredump.conf</filename>.
 109       Either <filename>/etc/sysctl.d/50-coredump.conf</filename>, or
 110       <filename>/run/sysctl.d/50-coredump.conf</filename>, or
 111       <filename>/usr/lib/sysctl.d/50-coredump.conf</filename> will be used, in the order
 112       of preference.</para>
 113     </example>
 114
 115     <para>See
 116     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 117     for various ways to directly apply sysctl settings.</para>
 118   </refsect1>
 119
 120   <refsect1>
 121     <title>See Also</title>
 122     <para>
 123       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 124       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 125       <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 126     </para>
 127   </refsect1>
 128
 129 </refentry>