<?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2014 Kay Sievers systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="systemd-timesyncd.service" conditional='ENABLE_TIMESYNCD'> <refentryinfo> <title>systemd-timesyncd.service</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Kay</firstname> <surname>Sievers</surname> <email>kay@vrfy.org</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>systemd-timesyncd.service</refentrytitle> <manvolnum>8</manvolnum> </refmeta> <refnamediv> <refname>systemd-timesyncd.service</refname> <refname>systemd-timesyncd</refname> <refpurpose>Network Time Synchronization</refpurpose> </refnamediv> <refsynopsisdiv> <para><filename>systemd-timesyncd.service</filename></para> <para><filename>/usr/lib/systemd/systemd-timesyncd</filename></para> </refsynopsisdiv> <refsect1> <title>Description</title> <para><filename>systemd-timesyncd</filename> is a system service that may be used to synchronize the local system clock with a remote Network Time Protocol server. It also saves the local time to disk every time the clock has been synchronized and uses this to possibly advance the system realtime clock on subsequent reboots to ensure it monotonically advances even if the system lacks a battery-buffered RTC chip.</para> <para>The NTP servers contacted are determined from the global settings in <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, the per-link static settings in <filename>.network</filename> files, and the per-link dynamic settings received over DHCP. See <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more details.</para> </refsect1> <refsect1> <title>Files</title> <variablelist> <varlistentry> <term><filename>/var/lib/systemd/clock</filename></term> <listitem> <para>This file contains the timestamp of last successful synchronization.</para> </listitem> </varlistentry> </variablelist> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry> </para> </refsect1> </refentry>