systemd/man/systemd-getty-generator.xml
Luca Boccassi ee3fddcc8a getty-generator: add kernel cmdline and env vars to disable it
systemd.getty_auto/rd.systemd.getty_auto/SYSTEMD_GETTY_AUTO can be used
to disable the generator. Enabled by default.
2021-11-18 10:38:48 +00:00

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4.1 KiB
XML

<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd-getty-generator">
<refentryinfo>
<title>systemd-getty-generator</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-getty-generator</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-getty-generator</refname>
<refpurpose>Generator for enabling getty instances on the
console</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>/usr/lib/systemd/system-generators/systemd-getty-generator</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>systemd-getty-generator</filename> is a generator that automatically instantiates
<filename>serial-getty@.service</filename> on the kernel console(s), if they can function as ttys and are
not provided by the virtual console subsystem. It will also instantiate
<filename>serial-getty@.service</filename> instances for virtualizer consoles, if execution in a
virtualized environment is detected. If execution in a container environment is detected, it will instead
enable <filename>console-getty.service</filename> for <filename>/dev/console</filename>, and
<filename>container-getty@.service</filename> instances for additional container pseudo TTYs as requested
by the container manager (see <ulink url="https://systemd.io/CONTAINER_INTERFACE"><filename>Container
Interface</filename></ulink>). This should ensure that the user is shown a login prompt at the right
place, regardless of which environment the system is started in. For example, it is sufficient to
redirect the kernel console with a kernel command line argument such as <varname>console=</varname> to
get both kernel messages and a getty prompt on a serial TTY. See <ulink
url="https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt"><filename>kernel-parameters.txt</filename></ulink>
for more information on the <varname>console=</varname> kernel parameter.</para>
<para><filename>systemd-getty-generator</filename> implements
<citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>Further information about configuration of gettys can be
found in
<ulink url="http://0pointer.de/blog/projects/serial-console.html">systemd
for Administrators, Part XVI: Gettys on Serial Consoles (and
Elsewhere)</ulink>.</para>
</refsect1>
<refsect1>
<title>Kernel Command Line</title>
<para><filename>systemd-getty-generator</filename> understands the following
<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
parameters:</para>
<variablelist class='kernel-commandline-options'>
<varlistentry>
<term><varname>systemd.getty_auto=</varname></term>
<listitem><para>this options take an optional boolean argument, and default to yes.
The generator is enabled by default, and a false value may be used to disable it.
</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Environment</title>
<variablelist class='environment-variables'>
<varlistentry>
<term><varname>$SYSTEMD_GETTY_AUTO</varname></term>
<listitem><para>This variable takes an optional boolean argument, and default to yes.
The generator is enabled by default, and a false value may be used to disable it.
</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>