man/timesyncd.conf.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="timesyncd.conf" conditional='ENABLE_TIMESYNCD'
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8   <refentryinfo>
   9     <title>timesyncd.conf</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>timesyncd.conf</refentrytitle>
  15     <manvolnum>5</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>timesyncd.conf</refname>
  20     <refname>timesyncd.conf.d</refname>
  21     <refpurpose>Network Time Synchronization configuration files</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <para><filename>/etc/systemd/timesyncd.conf</filename></para>
  26     <para><filename>/etc/systemd/timesyncd.conf.d/*.conf</filename></para>
  27     <para><filename>/run/systemd/timesyncd.conf.d/*.conf</filename></para>
  28     <para><filename>/usr/lib/systemd/timesyncd.conf.d/*.conf</filename></para>
  29   </refsynopsisdiv>
  30
  31   <refsect1>
  32     <title>Description</title>
  33
  34     <para>These configuration files control NTP network time synchronization. See
  35     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  36     for a general description of the syntax.</para>
  37   </refsect1>
  38
  39   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  40
  41   <refsect1>
  42     <title>Options</title>
  43
  44     <para>The following settings are configured in the <literal>[Time]</literal> section:</para>
  45
  46     <variablelist class='network-directives'>
  47
  48       <varlistentry>
  49         <term><varname>NTP=</varname></term>
  50         <listitem><para>A space-separated list of NTP server host
  51         names or IP addresses. During runtime this list is combined
  52         with any per-interface NTP servers acquired from
  53         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  54         systemd-timesyncd will contact all configured system or
  55         per-interface servers in turn until one is found that
  56         responds. When the empty string is assigned, the list of
  57         NTP servers is reset, and all assignments prior to this one
  58         will have no effect. This setting defaults to an empty
  59         list.</para></listitem>
  60       </varlistentry>
  61
  62       <varlistentry>
  63         <term><varname>FallbackNTP=</varname></term>
  64         <listitem><para>A space-separated list of NTP server host
  65         names or IP addresses to be used as the fallback NTP servers.
  66         Any per-interface NTP servers obtained from
  67         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  68         take precedence over this setting, as do any servers set via
  69         <varname>NTP=</varname> above. This setting is hence only used
  70         if no other NTP server information is known. When the empty
  71         string is assigned, the list of NTP servers is reset,
  72         and all assignments prior to this one will have no effect.
  73         If this option is not given, a compiled-in list of NTP servers
  74         is used instead.</para></listitem>
  75       </varlistentry>
  76
  77       <varlistentry>
  78         <term><varname>RootDistanceMaxSec=</varname></term>
  79         <listitem><para>Maximum acceptable root distance. Takes a time value (in seconds).
  80         Defaults to 5 seconds.</para></listitem>
  81       </varlistentry>
  82
  83       <varlistentry>
  84         <term><varname>PollIntervalMinSec=</varname></term>
  85         <term><varname>PollIntervalMaxSec=</varname></term>
  86         <listitem><para>The minimum and maximum poll intervals for NTP messages.
  87         Each setting takes a time value (in seconds).
  88         <varname>PollIntervalMinSec=</varname> must not be smaller than 16 seconds.
  89         <varname>PollIntervalMaxSec=</varname> must be larger than <varname>PollIntervalMinSec=</varname>.
  90         <varname>PollIntervalMinSec=</varname> defaults to 32 seconds, and
  91         <varname>PollIntervalMaxSec=</varname> defaults to 2048 seconds.</para></listitem>
  92       </varlistentry>
  93
  94     </variablelist>
  95   </refsect1>
  96
  97   <refsect1>
  98       <title>See Also</title>
  99       <para>
 100       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 101       <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 102       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 103       </para>
 104   </refsect1>
 105
 106 </refentry>