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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   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
  60                 system service that may be used to synchronize the
  61                 local system clock with a remote Network Time Protocol
  62                 server. It also saves the local time to disk every
  63                 time the clock has been synchronized and uses this to
  64                 possibly advance the system realtime clock on
  65                 subsequent reboots to ensure it
  66                 monotonically advances even if the system lacks a
  67                 battery-buffered RTC chip.</para>
  68
  69                 <para>The NTP servers contacted are determined from
  70                 the global settings in
  71                 <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  72                 the per-link static settings in
  73                 <filename>.network</filename> files, and the per-link
  74                 dynamic settings received over DHCP. See
  75                 <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  76                 for more details.</para>
  77         </refsect1>
  78
  79         <refsect1>
  80                 <title>Files</title>
  81
  82                 <variablelist>
  83                         <varlistentry>
  84                                 <term><filename>/var/lib/systemd/clock</filename></term>
  85
  86                                 <listitem>
  87                                         <para>This file contains the timestamp of last
  88                                         successful synchronization.</para>
  89                                 </listitem>
  90                         </varlistentry>
  91                 </variablelist>
  92         </refsect1>
  93
  94         <refsect1>
  95                 <title>See Also</title>
  96                 <para>
  97                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  98                         <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  99                         <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 100                         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 101                         <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 102                         <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 103                         <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 104                 </para>
 105         </refsect1>
 106
 107 </refentry>