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