man/systemd-sysctl.service.xml

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