<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!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+
-
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
--->
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="systemd-timedated.service" conditional='ENABLE_TIMEDATED'>
<refentryinfo>
<title>systemd-timedated.service</title>
<productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refsect1>
<title>Description</title>
- <para><filename>systemd-timedated</filename> is a system service
+ <para><filename>systemd-timedated.service</filename> is a system service
that may be used as a mechanism to change the system clock and
- timezone, as well as to enable/disable NTP time synchronization.
+ timezone, as well as to enable/disable network time synchronization.
<filename>systemd-timedated</filename> is automatically activated
on request and terminates itself when it is unused.</para>
<citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
is a command line client to this service.</para>
- <para>See the <ulink
- url="https://www.freedesktop.org/wiki/Software/systemd/timedated">
- developer documentation</ulink> for information about the APIs
- <filename>systemd-timedated</filename> provides.</para>
+ <para><filename>systemd-timedated</filename> currently offers access to
+ the following four settings:
+ <itemizedlist>
+ <listitem><para>The system time</para></listitem>
+
+ <listitem><para>The system timezone</para></listitem>
+
+ <listitem><para>A boolean controlling whether the system RTC is in local or UTC
+ timezone</para></listitem>
+
+ <listitem><para>Whether the time synchronization service is enabled/started or
+ disabled/stopped, see next section.</para></listitem>
+ </itemizedlist></para>
+
+ <para>See
+ <citerefentry><refentrytitle>org.freedesktop.timedate1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for information about the D-Bus API.</para>
</refsect1>
<refsect1>
- <title>Environment</title>
-
- <variablelist class='environment-variables'>
- <varlistentry>
- <term><varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname></term>
-
- <listitem><para>Colon-separated list of unit names of NTP client services.
- If not set, then
- <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- is used. See the entries of NTP related commands of
- <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- for details about this.</para>
-
- <para>Example:
- <programlisting>SYSTEMD_TIMEDATED_NTP_SERVICES=ntpd.service:chronyd.service:systemd-timesyncd.service</programlisting>
- </para></listitem>
- </varlistentry>
- </variablelist>
+ <title>List of network time synchronization services</title>
+
+ <para><command>systemd-timesyncd</command> will look for files with a <literal>.list</literal> extension
+ in <filename>ntp-units.d/</filename> directories. Each file is parsed as a list of unit names, one per
+ line. Empty lines and lines with comments (<literal>#</literal>) are ignored. Files are read from
+ <filename>/usr/lib/systemd/ntp-units.d/</filename> and the corresponding directories under
+ <filename>/etc/</filename>, <filename>/run/</filename>, <filename>/usr/local/lib/</filename>. Files in
+ <filename>/etc/</filename> override files with the same name in <filename>/run/</filename>,
+ <filename>/usr/local/lib/</filename>, and <filename>/usr/lib/</filename>. Files in
+ <filename>/run/</filename> override files with the same name under <filename>/usr/</filename>. Packages
+ should install their configuration files in <filename>/usr/lib/</filename> (distribution packages) or
+ <filename>/usr/local/lib/</filename> (local installs).</para>
+
+ <example>
+ <title><filename>ntp-units.d/</filename> entry for <command>systemd-timesyncd</command></title>
+ <programlisting># /usr/lib/systemd/ntp-units.d/80-systemd-timesync.list
+systemd-timesyncd.service
+</programlisting>
+ </example>
+
+ <para>If the environment variable <varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname> is set,
+ <command>systemd-timesyncd</command> will parse the contents of that variable as a colon-separated list
+ of unit names. When set, this variable overrides the file-based list described above.</para>
+
+ <example>
+ <title>An override that specifies that <command>chronyd</command> should be used if available</title>
+ <programlisting>SYSTEMD_TIMEDATED_NTP_SERVICES=chronyd.service:systemd-timesyncd.service</programlisting>
+ </example>
</refsect1>
+
<refsect1>
<title>See Also</title>
<para>