man/systemd-getty-generator.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   4   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   5 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   6 <refentry id="systemd-getty-generator" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>systemd-getty-generator</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>systemd-getty-generator</refentrytitle>
  15     <manvolnum>8</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>systemd-getty-generator</refname>
  20     <refpurpose>Generator for enabling getty instances on the
  21     console</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <para><filename>/usr/lib/systemd/system-generators/systemd-getty-generator</filename></para>
  26   </refsynopsisdiv>
  27
  28   <refsect1>
  29     <title>Description</title>
  30
  31     <para><filename>systemd-getty-generator</filename> is a generator that automatically instantiates
  32     <filename>serial-getty@.service</filename> on the kernel consoles, if they can function as ttys and are
  33     not provided by the virtual console subsystem. It will also instantiate
  34     <filename>serial-getty@.service</filename> instances for virtualizer consoles, if execution in a
  35     virtualized environment is detected. If execution in a container environment is detected, it will instead
  36     enable <filename>console-getty.service</filename> for <filename>/dev/console</filename>, and
  37     <filename>container-getty@.service</filename> instances for additional container pseudo TTYs as requested
  38     by the container manager (see <ulink url="https://systemd.io/CONTAINER_INTERFACE"><filename>Container
  39     Interface</filename></ulink>). This should ensure that the user is shown a login prompt at the right
  40     place, regardless of which environment the system is started in. For example, it is sufficient to
  41     redirect the kernel console with a kernel command line argument such as <varname>console=</varname> to
  42     get both kernel messages and a getty prompt on a serial TTY. See <ulink
  43     url="https://docs.kernel.org/admin-guide/kernel-parameters.html">The kernel's command-line
  44     parameters</ulink> for more information on the <varname>console=</varname> kernel parameter.</para>
  45
  46     <para><filename>systemd-getty-generator</filename> implements
  47     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  48
  49     <para>Further information about configuration of gettys can be
  50     found in
  51     <ulink url="https://0pointer.de/blog/projects/serial-console.html">systemd
  52     for Administrators, Part XVI: Gettys on Serial Consoles (and
  53     Elsewhere)</ulink>.</para>
  54   </refsect1>
  55
  56   <refsect1>
  57     <title>Kernel Command Line</title>
  58
  59     <para><filename>systemd-getty-generator</filename> understands the following
  60     <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  61     parameters:</para>
  62
  63     <variablelist class='kernel-commandline-options'>
  64       <varlistentry>
  65         <term><varname>systemd.getty_auto=</varname></term>
  66
  67         <listitem><para>this options take an optional boolean argument, and default to yes.
  68         The generator is enabled by default, and a false value may be used to disable it.
  69         </para>
  70
  71         <xi:include href="version-info.xml" xpointer="v250"/></listitem>
  72       </varlistentry>
  73     </variablelist>
  74   </refsect1>
  75
  76   <refsect1>
  77     <title>Environment</title>
  78
  79     <variablelist class='environment-variables'>
  80       <varlistentry>
  81         <term><varname>$SYSTEMD_GETTY_AUTO</varname></term>
  82
  83         <listitem><para>This variable takes an optional boolean argument, and default to yes.
  84         The generator is enabled by default, and a false value may be used to disable it.
  85         </para>
  86
  87         <xi:include href="version-info.xml" xpointer="v250"/></listitem>
  88       </varlistentry>
  89     </variablelist>
  90   </refsect1>
  91
  92   <refsect1>
  93     <title>System Credentials</title>
  94
  95     <variablelist class='system-credentials'>
  96       <varlistentry>
  97         <term><varname>getty.ttys.serial</varname></term>
  98         <term><varname>getty.ttys.container</varname></term>
  99
 100         <listitem><para>These system credentials may be used to spawn additional login prompts on selected
 101         TTYs. The two credentials should contain a newline-separated list of TTY names to spawn instances of
 102         <filename>serial-getty@.service</filename> (in case of <varname>getty.ttys.serial</varname>) and
 103         <filename>container-getty@.service</filename> (in case of <varname>getty.ttys.container</varname>)
 104         on.</para>
 105
 106         <xi:include href="version-info.xml" xpointer="v254"/></listitem>
 107       </varlistentry>
 108     </variablelist>
 109   </refsect1>
 110
 111   <refsect1>
 112     <title>See Also</title>
 113     <para>
 114       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 115       <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 116       <citerefentry><refentrytitle>systemd.system-credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 117       <citerefentry project='man-pages'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 118     </para>
 119   </refsect1>
 120
 121 </refentry>