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

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<refentry id="systemd-time-wait-sync.service" conditional='ENABLE_TIMESYNCD'>

  <refentryinfo>
    <title>systemd-time-wait-sync.service</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-time-wait-sync.service</refentrytitle>
    <manvolnum>8</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-time-wait-sync.service</refname>
    <refname>systemd-time-wait-sync</refname>
    <refpurpose>Wait until kernel time is synchronized</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename>systemd-time-wait-sync.service</filename></para>
    <para><filename>/usr/lib/systemd/systemd-time-wait-sync</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><filename>systemd-time-wait-sync</filename> is a system service that delays the start of units that
    are ordered after <filename>time-sync.target</filename> (see
    <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
    details) until the system time has been synchronized with an accurate remote reference time source by
    <filename>systemd-timesyncd.service</filename>.</para>

    <para><filename>systemd-timesyncd.service</filename> notifies <filename>systemd-time-wait-sync</filename>
    about successful synchronization.  <filename>systemd-time-wait-sync</filename> also tries to detect when
    the kernel marks the system clock as synchronized, but this detection is not reliable and is intended
    only as a fallback for compatibility with alternative NTP services that can be used to synchronize time
    (e.g., ntpd, chronyd).</para>
  </refsect1>

  <refsect1>
    <title>Files</title>

    <variablelist>
      <varlistentry>
        <term><filename>/run/systemd/timesync/synchronized</filename></term>

        <listitem>
          <para>The presence of this file indicates to this service that the system clock has been synchronized.</para>
        </listitem>

      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
    </para>
  </refsect1>

</refentry>