man/systemd-timesyncd.service.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
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   6   This file is part of systemd.
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   8   Copyright 2014 Kay Sievers
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  23
  24 <refentry id="systemd-timesyncd.service" conditional='ENABLE_TIMESYNCD'>
  25
  26   <refentryinfo>
  27     <title>systemd-timesyncd.service</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Kay</firstname>
  34         <surname>Sievers</surname>
  35         <email>kay@vrfy.org</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>systemd-timesyncd.service</refentrytitle>
  42     <manvolnum>8</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemd-timesyncd.service</refname>
  47     <refname>systemd-timesyncd</refname>
  48     <refpurpose>Network Time Synchronization</refpurpose>
  49   </refnamediv>
  50
  51   <refsynopsisdiv>
  52     <para><filename>systemd-timesyncd.service</filename></para>
  53     <para><filename>/usr/lib/systemd/systemd-timesyncd</filename></para>
  54   </refsynopsisdiv>
  55
  56   <refsect1>
  57     <title>Description</title>
  58
  59     <para><filename>systemd-timesyncd</filename> is a system service
  60     that may be used to synchronize the local system clock with a
  61     remote Network Time Protocol server. It also saves the local time
  62     to disk every time the clock has been synchronized and uses this
  63     to possibly advance the system realtime clock on subsequent
  64     reboots to ensure it monotonically advances even if the system
  65     lacks a battery-buffered RTC chip.</para>
  66
  67     <para>The NTP servers contacted are determined from the global
  68     settings in
  69     <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  70     the per-link static settings in <filename>.network</filename>
  71     files, and the per-link dynamic settings received over DHCP. See
  72     <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  73     for more details.</para>
  74   </refsect1>
  75
  76   <refsect1>
  77     <title>Files</title>
  78
  79     <variablelist>
  80       <varlistentry>
  81         <term><filename>/var/lib/systemd/clock</filename></term>
  82
  83         <listitem>
  84           <para>This file contains the timestamp of last successful
  85           synchronization.</para>
  86         </listitem>
  87       </varlistentry>
  88     </variablelist>
  89   </refsect1>
  90
  91   <refsect1>
  92     <title>See Also</title>
  93     <para>
  94       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  95       <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  96       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  97       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  98       <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  99       <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 100       <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 101     </para>
 102   </refsect1>
 103
 104 </refentry>