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systemd/man/systemd-time-wait-sync.service.xml
Peter A. Bigot 5c3376efcd time-sync-wait: add service (#8494)
This one-shot service waits until the kernel time has been set to
synchronized.
2018-03-21 12:42:04 +01:00

92 lines
3.5 KiB
XML

<?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">
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<refentry id="systemd-time-wait-sync.service" conditional='ENABLE_TIMESYNCD'>
<refentryinfo>
<title>systemd-time-wait-sync.service</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Peter</firstname>
<surname>Bigot</surname>
<email>pab@pabigot.com</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-time-wait-sync.service</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-time-wait-sync.service</refname>
<refname>systemd-time-wait-sync</refname>
<refpurpose>Wait Until Kernel Time Synchronized</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>systemd-time-wait-sync.service</filename></para>
<para><filename>/usr/lib/systemd/systemd-time-wait-sync</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>systemd-time-wait-sync</filename> is a system service that delays the start of units that depend on
<filename>time-sync.target</filename> until <filename>systemd-timesyncd.service</filename> or something else has
set the system time and marked it as synchronized. Reaching this state generally requires synchronization with an
external source, such as an NTP server.</para>
<para>When this unit is not enabled the <filename>time-sync.target</filename> synchronization point may be reached
as soon as the system time is advanced by <filename>systemd-timesyncd.service</filename> to the time stored at the
last shutdown. That time may not meet the expectations of dependent services that require an accurate
clock.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>This service works correctly with a time synchronization service like
<filename>systemd-timesyncd.service</filename> that uses the same protocol as NTP to set the time from a
synchronized source. When used with time synchronization services that follow a different protocol the event of
setting synchronized time may not be detected in which case this service will not complete.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
</para>
</refsect1>
</refentry>