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">
6 This file is part of systemd.
8 Copyright 2014 Kay Sievers
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 <refentry id="systemd-timesyncd.service" conditional='ENABLE_TIMESYNCD'>
27 <title>systemd-timesyncd.service</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Kay</firstname>
34 <surname>Sievers</surname>
35 <email>kay@vrfy.org</email>
41 <refentrytitle>systemd-timesyncd.service</refentrytitle>
42 <manvolnum>8</manvolnum>
46 <refname>systemd-timesyncd.service</refname>
47 <refname>systemd-timesyncd</refname>
48 <refpurpose>Network Time Synchronization</refpurpose>
52 <para><filename>systemd-timesyncd.service</filename></para>
53 <para><filename>/usr/lib/systemd/systemd-timesyncd</filename></para>
57 <title>Description</title>
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>
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>
80 <title>See Also</title>
82 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
83 <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
84 <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
85 <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
86 <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
87 <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
88 <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>