man/systemd-time-wait-sync.service.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="systemd-time-wait-sync.service" conditional='ENABLE_TIMESYNCD'
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-time-wait-sync.service</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-time-wait-sync.service</refentrytitle>
  16     <manvolnum>8</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-time-wait-sync.service</refname>
  21     <refname>systemd-time-wait-sync</refname>
  22     <refpurpose>Wait until kernel time is synchronized</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <para><filename>systemd-time-wait-sync.service</filename></para>
  27     <para><filename>/usr/lib/systemd/systemd-time-wait-sync</filename></para>
  28   </refsynopsisdiv>
  29
  30   <refsect1>
  31     <title>Description</title>
  32
  33     <para><filename>systemd-time-wait-sync</filename> is a system service that delays the start of units that
  34     are ordered after <filename>time-sync.target</filename> (see
  35     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
  36     details) until the system time has been synchronized with an accurate remote reference time source by
  37     <filename>systemd-timesyncd.service</filename>.</para>
  38
  39     <para><filename>systemd-timesyncd.service</filename> notifies <filename>systemd-time-wait-sync</filename>
  40     about successful synchronization.  <filename>systemd-time-wait-sync</filename> also tries to detect when
  41     the kernel marks the system clock as synchronized, but this detection is not reliable and is intended
  42     only as a fallback for compatibility with alternative NTP services that can be used to synchronize time
  43     (e.g., ntpd, chronyd).</para>
  44   </refsect1>
  45
  46   <refsect1>
  47     <title>Files</title>
  48
  49     <variablelist>
  50       <varlistentry>
  51         <term><filename>/run/systemd/timesync/synchronized</filename></term>
  52
  53         <listitem>
  54           <para>The presence of this file indicates to this service that the system clock has been synchronized.</para>
  55
  56         <xi:include href="version-info.xml" xpointer="v239"/>
  57         </listitem>
  58
  59       </varlistentry>
  60     </variablelist>
  61
  62   </refsect1>
  63
  64   <refsect1>
  65     <title>See Also</title>
  66     <para>
  67       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  68       <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
  69       <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  70     </para>
  71   </refsect1>
  72
  73 </refentry>