man/systemd-timesyncd.service.xml

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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
  75     <para><citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  76     <command>set-ntp</command> command may be used to enable and
  77     start, or disable and stop this service.</para>
  78   </refsect1>
  79
  80   <refsect1>
  81     <title>Files</title>
  82
  83     <variablelist>
  84       <varlistentry>
  85         <term><filename>/var/lib/systemd/clock</filename></term>
  86
  87         <listitem>
  88           <para>This file contains the timestamp of the last successful
  89           synchronization.</para>
  90         </listitem>
  91       </varlistentry>
  92     </variablelist>
  93   </refsect1>
  94
  95   <refsect1>
  96     <title>See Also</title>
  97     <para>
  98       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  99       <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 100       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 101       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 102       <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 103       <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 104       <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 105     </para>
 106   </refsect1>
 107
 108 </refentry>