man/timesyncd.conf.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
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   8
   9 <refentry id="timesyncd.conf" conditional='ENABLE_TIMESYNCD'
  10     xmlns:xi="http://www.w3.org/2001/XInclude">
  11   <refentryinfo>
  12     <title>timesyncd.conf</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>timesyncd.conf</refentrytitle>
  18     <manvolnum>5</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>timesyncd.conf</refname>
  23     <refname>timesyncd.conf.d</refname>
  24     <refpurpose>Network Time Synchronization configuration files</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <para><filename>/etc/systemd/timesyncd.conf</filename></para>
  29     <para><filename>/etc/systemd/timesyncd.conf.d/*.conf</filename></para>
  30     <para><filename>/run/systemd/timesyncd.conf.d/*.conf</filename></para>
  31     <para><filename>/usr/lib/systemd/timesyncd.conf.d/*.conf</filename></para>
  32   </refsynopsisdiv>
  33
  34   <refsect1>
  35     <title>Description</title>
  36
  37     <para>These configuration files control NTP network time synchronization. See
  38     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  39     for a general description of the syntax.</para>
  40   </refsect1>
  41
  42   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  43
  44   <refsect1>
  45     <title>Options</title>
  46
  47     <para>The following settings are configured in the <literal>[Time]</literal> section:</para>
  48
  49     <variablelist class='network-directives'>
  50
  51       <varlistentry>
  52         <term><varname>NTP=</varname></term>
  53         <listitem><para>A space-separated list of NTP server host
  54         names or IP addresses. During runtime this list is combined
  55         with any per-interface NTP servers acquired from
  56         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  57         systemd-timesyncd will contact all configured system or
  58         per-interface servers in turn until one is found that
  59         responds. When the empty string is assigned, the list of
  60         NTP servers is reset, and all assignments prior to this one
  61         will have no effect. This setting defaults to an empty
  62         list.</para></listitem>
  63       </varlistentry>
  64
  65       <varlistentry>
  66         <term><varname>FallbackNTP=</varname></term>
  67         <listitem><para>A space-separated list of NTP server host
  68         names or IP addresses to be used as the fallback NTP servers.
  69         Any per-interface NTP servers obtained from
  70         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  71         take precedence over this setting, as do any servers set via
  72         <varname>NTP=</varname> above. This setting is hence only used
  73         if no other NTP server information is known. When the empty
  74         string is assigned, the list of NTP servers is reset,
  75         and all assignments prior to this one will have no effect.
  76         If this option is not given, a compiled-in list of NTP servers
  77         is used instead.</para></listitem>
  78       </varlistentry>
  79
  80       <varlistentry>
  81         <term><varname>RootDistanceMaxSec=</varname></term>
  82         <listitem><para>Maximum acceptable root distance. Takes a time value (in seconds).
  83         Defaults to 5 seconds.</para></listitem>
  84       </varlistentry>
  85
  86       <varlistentry>
  87         <term><varname>PollIntervalMinSec=</varname></term>
  88         <term><varname>PollIntervalMaxSec=</varname></term>
  89         <listitem><para>The minimum and maximum poll intervals for NTP messages.
  90         Each setting takes a time value (in seconds).
  91         <varname>PollIntervalMinSec=</varname> must not be smaller than 16 seconds.
  92         <varname>PollIntervalMaxSec=</varname> must be larger than <varname>PollIntervalMinSec=</varname>.
  93         <varname>PollIntervalMinSec=</varname> defaults to 32 seconds, and
  94         <varname>PollIntervalMaxSec=</varname> defaults to 2048 seconds.</para></listitem>
  95       </varlistentry>
  96
  97     </variablelist>
  98   </refsect1>
  99
 100   <refsect1>
 101       <title>See Also</title>
 102       <para>
 103       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 104       <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 105       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 106       </para>
 107   </refsect1>
 108
 109 </refentry>