man/systemd-sysctl.service.xml

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