man/systemd-udevd.service.xml

   1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <refentry id="systemd-udevd.service"
   6           xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>systemd-udevd.service</title>
  10     <productname>systemd</productname>
  11     <authorgroup>
  12       <author>
  13         <contrib>Developer</contrib>
  14         <firstname>Kay</firstname>
  15         <surname>Sievers</surname>
  16         <email>kay@vrfy.org</email>
  17       </author>
  18     </authorgroup>
  19   </refentryinfo>
  20
  21   <refmeta>
  22     <refentrytitle>systemd-udevd.service</refentrytitle>
  23     <manvolnum>8</manvolnum>
  24   </refmeta>
  25
  26   <refnamediv>
  27     <refname>systemd-udevd.service</refname>
  28     <refname>systemd-udevd-control.socket</refname>
  29     <refname>systemd-udevd-kernel.socket</refname>
  30     <refname>systemd-udevd</refname>
  31     <refpurpose>Device event managing daemon</refpurpose>
  32   </refnamediv>
  33
  34   <refsynopsisdiv>
  35     <para><filename>systemd-udevd.service</filename></para>
  36     <para><filename>systemd-udevd-control.socket</filename></para>
  37     <para><filename>systemd-udevd-kernel.socket</filename></para>
  38
  39     <cmdsynopsis>
  40       <command>/usr/lib/systemd/systemd-udevd</command>
  41       <arg><option>--daemon</option></arg>
  42       <arg><option>--debug</option></arg>
  43       <arg><option>--children-max=</option></arg>
  44       <arg><option>--exec-delay=</option></arg>
  45       <arg><option>--event-timeout=</option></arg>
  46       <arg><option>--resolve-names=early|late|never</option></arg>
  47       <arg><option>--version</option></arg>
  48       <arg><option>--help</option></arg>
  49     </cmdsynopsis>
  50
  51   </refsynopsisdiv>
  52
  53   <refsect1><title>Description</title>
  54     <para><command>systemd-udevd</command> listens to kernel uevents.
  55     For every event, systemd-udevd executes matching instructions
  56     specified in udev rules. See <citerefentry>
  57     <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
  58     </citerefentry>.</para>
  59
  60     <para>The behavior of the daemon can be configured using
  61     <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  62     its command line options, environment variables, and on the kernel
  63     command line, or changed dynamically with <command>udevadm
  64     control</command>.
  65     </para>
  66   </refsect1>
  67
  68   <refsect1><title>Options</title>
  69     <variablelist>
  70       <varlistentry>
  71         <term><option>--daemon</option></term>
  72         <listitem>
  73           <para>Detach and run in the background.</para>
  74         </listitem>
  75       </varlistentry>
  76
  77       <varlistentry>
  78         <term><option>--debug</option></term>
  79         <listitem>
  80           <para>Print debug messages to standard error.</para>
  81         </listitem>
  82       </varlistentry>
  83
  84       <varlistentry>
  85         <term><option>--children-max=</option></term>
  86         <listitem>
  87           <para>Limit the number of events executed in parallel.</para>
  88         </listitem>
  89       </varlistentry>
  90
  91       <varlistentry>
  92         <term><option>--exec-delay=</option></term>
  93         <listitem>
  94           <para>Delay the execution of <varname>RUN</varname>
  95           instructions by the given number of seconds. This option
  96           might be useful when debugging system crashes during
  97           coldplug caused by loading non-working kernel
  98           modules.</para>
  99         </listitem>
 100       </varlistentry>
 101
 102       <varlistentry>
 103         <term><option>--event-timeout=</option></term>
 104         <listitem>
 105           <para>Set the number of seconds to wait for events to finish. After
 106           this time, the event will be terminated. The default is 180 seconds.</para>
 107         </listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <term><option>--resolve-names=</option></term>
 112         <listitem>
 113           <para>Specify when systemd-udevd should resolve names of users and groups.
 114           When set to <option>early</option> (the default), names will be
 115           resolved when the rules are parsed.  When set to
 116           <option>late</option>, names will be resolved for every event.
 117           When set to <option>never</option>, names will never be resolved
 118           and all devices will be owned by root.</para>
 119         </listitem>
 120       </varlistentry>
 121
 122       <varlistentry>
 123         <term><option>--help</option></term>
 124
 125         <xi:include href="standard-options.xml" xpointer="help-text" />
 126       </varlistentry>
 127       <xi:include href="standard-options.xml" xpointer="version" />
 128     </variablelist>
 129   </refsect1>
 130
 131   <refsect1><title>Kernel command line</title>
 132     <variablelist class='kernel-commandline-options'>
 133       <para>Parameters starting with "rd." will be read when
 134       <command>systemd-udevd</command> is used in an initrd.</para>
 135       <varlistentry>
 136         <term><varname>udev.log-priority=</varname></term>
 137         <term><varname>rd.udev.log-priority=</varname></term>
 138         <listitem>
 139           <para>Set the log level.</para>
 140         </listitem>
 141       </varlistentry>
 142       <varlistentry>
 143         <term><varname>udev.children-max=</varname></term>
 144         <term><varname>rd.udev.children-max=</varname></term>
 145         <listitem>
 146           <para>Limit the number of events executed in parallel.</para>
 147         </listitem>
 148       </varlistentry>
 149       <varlistentry>
 150         <term><varname>udev.exec-delay=</varname></term>
 151         <term><varname>rd.udev.exec-delay=</varname></term>
 152         <listitem>
 153           <para>Delay the execution of <varname>RUN</varname> instructions by the given
 154           number of seconds. This option might be useful when
 155           debugging system crashes during coldplug caused by loading
 156           non-working kernel modules.</para>
 157         </listitem>
 158       </varlistentry>
 159       <varlistentry>
 160         <term><varname>udev.event-timeout=</varname></term>
 161         <term><varname>rd.udev.event-timeout=</varname></term>
 162         <listitem>
 163           <para>Wait for events to finish up to the given number
 164           of seconds. This option might be useful if events are
 165           terminated due to kernel drivers taking too long to initialize.</para>
 166         </listitem>
 167       </varlistentry>
 168       <varlistentry>
 169         <term><varname>net.ifnames=</varname></term>
 170         <listitem>
 171           <para>Network interfaces are renamed to give them predictable names
 172           when possible. It is enabled by default; specifying 0 disables it.</para>
 173         </listitem>
 174       </varlistentry>
 175     </variablelist>
 176     <!-- when adding entries here, consider also adding them
 177          in kernel-command-line.xml -->
 178  </refsect1>
 179
 180   <refsect1>
 181     <title>See Also</title>
 182     <para>
 183       <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 184       <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 185       <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 186     </para>
 187   </refsect1>
 188 </refentry>