* man: Advertise systemd-time-wait-sync.service more
The description of time-sync.target says that NTP services *should* pull
that target, but doesn't mention that e.g. systemd-timesyncd.service
doesn't actually do that. As a result, time-sync.target is reached way
earlier than people expect; see #5097, #8861, #11008.
systemd provides systemd-time-wait-sync.service to ameliorate this
problem, but doesn't feature it prominently in relevant manpages. In
fact, it's only mentioned in passing in systemd-timesyncd.service(8). As
a result, I ended up re-implementing that service, and I'm not the first
one: https://github.com/NixOS/nixpkgs/pull/51338
This patch adds a mention right in the description of time-sync.target,
which will hopefully raise awareness of this helper service.
in. systemd automatically adds dependencies of type
<varname>After=</varname> for this target unit to all SysV
init script service units with an LSB header referring to
- the <literal>$time</literal> facility. </para>
+ the <literal>$time</literal> facility, and also to all timer
+ units with at least one <varname>OnCalendar=</varname>
+ directive. </para>
+
+ <para>This target might get reached before the clock is actually synchronized to an accurate reference
+ clock. To prevent that, enable
+ <citerefentry><refentrytitle>systemd-time-wait-sync.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ if you're using
+ <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ or an equivalent service for other NTP implementations.</para>
</listitem>
</varlistentry>
</variablelist>
projects / thirdparty / systemd.git / commitdiff
