man/systemd-sysctl.service.xml

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   7   This file is part of systemd.
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   9   Copyright 2012 Lennart Poettering
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  24 <refentry id="systemd-sysctl.service"
  25     xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27   <refentryinfo>
  28     <title>systemd-sysctl.service</title>
  29     <productname>systemd</productname>
  30
  31     <authorgroup>
  32       <author>
  33         <contrib>Developer</contrib>
  34         <firstname>Lennart</firstname>
  35         <surname>Poettering</surname>
  36         <email>lennart@poettering.net</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40
  41   <refmeta>
  42     <refentrytitle>systemd-sysctl.service</refentrytitle>
  43     <manvolnum>8</manvolnum>
  44   </refmeta>
  45
  46   <refnamediv>
  47     <refname>systemd-sysctl.service</refname>
  48     <refname>systemd-sysctl</refname>
  49     <refpurpose>Configure kernel parameters at boot</refpurpose>
  50   </refnamediv>
  51
  52   <refsynopsisdiv>
  53     <cmdsynopsis>
  54       <command>/usr/lib/systemd/systemd-sysctl</command>
  55       <arg choice="opt" rep="repeat">OPTIONS</arg>
  56       <arg choice="opt" rep="repeat"><replaceable>CONFIGFILE</replaceable></arg>
  57     </cmdsynopsis>
  58     <para><filename>systemd-sysctl.service</filename></para>
  59   </refsynopsisdiv>
  60
  61   <refsect1>
  62     <title>Description</title>
  63
  64     <para><filename>systemd-sysctl.service</filename> is an early boot
  65     service that configures
  66     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  67     kernel parameters by invoking <command>/usr/lib/systemd/systemd-sysctl</command>.</para>
  68
  69     <para>When invoked with no arguments, <command>/usr/lib/systemd/systemd-sysctl</command> applies
  70     all directives from configuration files listed in
  71     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  72     If one or more filenames are passed on the command line, only the directives in these files are
  73     applied.</para>
  74
  75     <para>In addition, <option>--prefix=</option> option may be used to limit which sysctl
  76     settings are applied.</para>
  77
  78     <para>See
  79     <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  80     for information about the configuration of sysctl settings. After sysctl configuration is
  81     changed on disk, it must be written to the files in <filename>/proc/sys</filename> before it
  82     takes effect. It is possible to update specific settings, or simply to reload all configuration,
  83     see Examples below.</para>
  84   </refsect1>
  85
  86   <refsect1><title>Options</title>
  87     <variablelist>
  88       <varlistentry id='prefix'>
  89         <term><option>--prefix=</option></term>
  90         <listitem>
  91           <para>Only apply rules with the specified prefix.</para>
  92         </listitem>
  93       </varlistentry>
  94
  95       <xi:include href="standard-options.xml" xpointer="help" />
  96       <xi:include href="standard-options.xml" xpointer="version" />
  97
  98     </variablelist>
  99   </refsect1>
 100
 101   <refsect1>
 102     <title>Examples</title>
 103
 104     <example>
 105       <title>Reset all sysctl settings</title>
 106
 107       <programlisting>systemctl restart systemd-sysctl</programlisting>
 108     </example>
 109
 110     <example>
 111       <title>View coredump handler configuration</title>
 112
 113       <programlisting># sysctl kernel.core_pattern
 114 kernel.core_pattern = |/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t %P %I
 115 </programlisting>
 116     </example>
 117
 118     <example>
 119       <title>Update coredump handler configuration</title>
 120
 121       <programlisting># /usr/lib/systemd/systemd-sysctl --prefix kernel.core_pattern</programlisting>
 122
 123       <para>This searches all the directories listed in
 124       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 125       for configuration files and writes <filename>/proc/sys/kernel/core_pattern</filename>.</para>
 126     </example>
 127
 128     <example>
 129       <title>Update coredump handler configuration according to a specific file</title>
 130
 131       <programlisting># /usr/lib/systemd/systemd-sysctl 50-coredump.conf</programlisting>
 132
 133       <para>This applies all the settings found in <filename>50-coredump.conf</filename>.
 134       Either <filename>/etc/sysctl.d/50-coredump.conf</filename>, or
 135       <filename>/run/sysctl.d/50-coredump.conf</filename>, or
 136       <filename>/usr/lib/sysctl.d/50-coredump.conf</filename> will be used, in the order
 137       of preference.</para>
 138     </example>
 139
 140     <para>See
 141     <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 142     for various ways to directly apply sysctl settings.</para>
 143   </refsect1>
 144
 145   <refsect1>
 146     <title>See Also</title>
 147     <para>
 148       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 149       <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 150       <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 151     </para>
 152   </refsect1>
 153
 154 </refentry>