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
8  <refentryinfo>
9    <title>systemd-time-wait-sync.service</title>
10    <productname>systemd</productname>
11  </refentryinfo>
12
13  <refmeta>
14    <refentrytitle>systemd-time-wait-sync.service</refentrytitle>
15    <manvolnum>8</manvolnum>
16  </refmeta>
17
18  <refnamediv>
19    <refname>systemd-time-wait-sync.service</refname>
20    <refname>systemd-time-wait-sync</refname>
21    <refpurpose>Wait until kernel time is synchronized</refpurpose>
22  </refnamediv>
23
24  <refsynopsisdiv>
25    <para><filename>systemd-time-wait-sync.service</filename></para>
26    <para><filename>/usr/lib/systemd/systemd-time-wait-sync</filename></para>
27  </refsynopsisdiv>
28
29  <refsect1>
30    <title>Description</title>
31
32    <para><filename>systemd-time-wait-sync</filename> is a system service that delays the start of units that
33    are ordered after <filename>time-sync.target</filename> (see
34    <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
35    details) until the system time has been synchronized with an accurate remote reference time source by
36    <filename>systemd-timesyncd.service</filename>.</para>
37
38    <para><filename>systemd-timesyncd.service</filename> notifies <filename>systemd-time-wait-sync</filename>
39    about successful synchronization.  <filename>systemd-time-wait-sync</filename> also tries to detect when
40    the kernel marks the system clock as synchronized, but this detection is not reliable and is intended
41    only as a fallback for compatibility with alternative NTP services that can be used to synchronize time
42    (e.g., ntpd, chronyd).</para>
43  </refsect1>
44
45  <refsect1>
46    <title>Files</title>
47
48    <variablelist>
49      <varlistentry>
50        <term><filename>/run/systemd/timesync/synchronized</filename></term>
51
52        <listitem>
53          <para>The presence of this file indicates to this service that the system clock has been synchronized.</para>
54        </listitem>
55
56      </varlistentry>
57    </variablelist>
58
59  </refsect1>
60
61  <refsect1>
62    <title>See Also</title>
63    <para>
64      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
65      <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
66      <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
67    </para>
68  </refsect1>
69
70</refentry>
71