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<refentry id="systemd.timer">
- <refentryinfo>
- <title>systemd.timer</title>
- <productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
- </refentryinfo>
-
- <refmeta>
- <refentrytitle>systemd.timer</refentrytitle>
- <manvolnum>5</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>systemd.timer</refname>
- <refpurpose>systemd timer configuration files</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <para><filename>systemd.timer</filename></para>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para>A unit configuration file whose name ends in
- <filename>.timer</filename> encodes information about
- a timer controlled and supervised by systemd, for
- timer-based activation.</para>
-
- <para>This man page lists the configuration options
- specific to this unit type. See
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for the common options of all unit configuration
- files. The common configuration items are configured
- in the generic [Unit] and [Install] sections. The
- timer specific configuration options are configured in
- the [Timer] section.</para>
-
- <para>For each timer file, a matching unit file must
- exist, describing the unit to activate when the timer
- elapses. By default, a service by the same name as the
- timer (except for the suffix) is activated. Example: a
- timer file <filename>foo.timer</filename> activates a
- matching service <filename>foo.service</filename>. The
- unit to activate may be controlled by
- <varname>Unit=</varname> (see below).</para>
-
- <para>Unless <varname>DefaultDependencies=</varname>
- is set to <option>false</option>, timer units will
- implicitly have dependencies of type
- <varname>Conflicts=</varname> and
- <varname>Before=</varname> on
- <filename>shutdown.target</filename>. These ensure
- that timer units are stopped cleanly prior to system
- shutdown. Only timer units involved with early boot or
- late system shutdown should disable this
- option.</para>
- </refsect1>
-
- <refsect1>
- <title>Options</title>
-
- <para>Timer files must include a [Timer] section,
- which carries information about the timer it
- defines. The options specific to the [Timer] section
- of timer units are the following:</para>
-
- <variablelist>
- <varlistentry>
- <term><varname>OnActiveSec=</varname></term>
- <term><varname>OnBootSec=</varname></term>
- <term><varname>OnStartupSec=</varname></term>
- <term><varname>OnUnitActiveSec=</varname></term>
- <term><varname>OnUnitInactiveSec=</varname></term>
-
- <listitem><para>Defines timers
- relative to different starting points:
- <varname>OnActiveSec=</varname> defines a
- timer relative to the moment the timer
- itself is
- activated. <varname>OnBootSec=</varname>
- defines a timer relative to when the
- machine was booted
- up. <varname>OnStartupSec=</varname>
- defines a timer relative to when
- systemd was
- started. <varname>OnUnitActiveSec=</varname>
- defines a timer relative to when the
- unit the timer is activating was last
- activated. <varname>OnUnitInactiveSec=</varname>
- defines a timer relative to when the
- unit the timer is activating was last
- deactivated.</para>
-
- <para>Multiple directives may be
- combined of the same and of different
- types. For example, by combining
- <varname>OnBootSec=</varname> and
- <varname>OnUnitActiveSec=</varname> it is
- possible to define a timer that
- elapses in regular intervals and
- activates a specific service each
- time.</para>
-
- <para>The arguments to the directives
- are time spans configured in
- seconds. Example: "OnBootSec=50" means
- 50s after boot-up. The argument may
- also include time units. Example:
- "OnBootSec=5h 30min" means 5 hours and 30
- minutes after boot-up. For details
- about the syntax of time spans see
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
-
- <para>If a timer configured with
- <varname>OnBootSec=</varname> or
- <varname>OnStartupSec=</varname> is
- already in the past when the timer
- unit is activated, it will immediately
- elapse and the configured unit is
- started. This is not the case for
- timers defined in the other
- directives.</para></listitem>
-
- <para>These are monotonic timers,
- independent of wall-clock time and timezones. If the
- computer is temporarily suspended, the
- monotonic clock stops too.</para>
-
- </varlistentry>
- <varlistentry>
- <term><varname>Unit=</varname></term>
-
- <listitem><para>The unit to activate
- when this timer elapses. The argument is a
- unit name, whose suffix is not
- <filename>.timer</filename>. If not
- specified, this value defaults to a
- service that has the same name as the
- timer unit, except for the
- suffix. (See above.) It is recommended
- that the unit name that is activated
- and the unit name of the timer unit
- are named identically, except for the
- suffix.</para></listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
-
- <refsect1>
- <title>See Also</title>
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- </para>
- </refsect1>
+ <refentryinfo>
+ <title>systemd.timer</title>
+ <productname>systemd</productname>
+
+ <authorgroup>
+ <author>
+ <contrib>Developer</contrib>
+ <firstname>Lennart</firstname>
+ <surname>Poettering</surname>
+ <email>lennart@poettering.net</email>
+ </author>
+ </authorgroup>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>systemd.timer</refentrytitle>
+ <manvolnum>5</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>systemd.timer</refname>
+ <refpurpose>Timer unit configuration</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename><replaceable>timer</replaceable>.timer</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>A unit configuration file whose name ends in
+ <literal>.timer</literal> encodes information about a timer
+ controlled and supervised by systemd, for timer-based
+ activation.</para>
+
+ <para>This man page lists the configuration options specific to
+ this unit type. See
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for the common options of all unit configuration files. The common
+ configuration items are configured in the generic [Unit] and
+ [Install] sections. The timer specific configuration options are
+ configured in the [Timer] section.</para>
+
+ <para>For each timer file, a matching unit file must exist,
+ describing the unit to activate when the timer elapses. By
+ default, a service by the same name as the timer (except for the
+ suffix) is activated. Example: a timer file
+ <filename>foo.timer</filename> activates a matching service
+ <filename>foo.service</filename>. The unit to activate may be
+ controlled by <varname>Unit=</varname> (see below).</para>
+
+ <para>Unless <varname>DefaultDependencies=</varname> is set to
+ <option>false</option>, all timer units will implicitly have
+ dependencies of type <varname>Conflicts=</varname> and
+ <varname>Before=</varname> on <filename>shutdown.target</filename>
+ to ensure that they are stopped cleanly prior to system shutdown.
+ Timer units with at least one <varname>OnCalendar=</varname>
+ directive will have an additional <varname>After=</varname>
+ dependency on <filename>timer-sync.target</filename> to avoid
+ being started before the system clock has been correctly set. Only
+ timer units involved with early boot or late system shutdown
+ should disable the <varname>DefaultDependencies=</varname>
+ option.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Options</title>
+
+ <para>Timer files must include a [Timer] section, which carries
+ information about the timer it defines. The options specific to
+ the [Timer] section of timer units are the following:</para>
+
+ <variablelist class='unit-directives'>
+ <varlistentry>
+ <term><varname>OnActiveSec=</varname></term>
+ <term><varname>OnBootSec=</varname></term>
+ <term><varname>OnStartupSec=</varname></term>
+ <term><varname>OnUnitActiveSec=</varname></term>
+ <term><varname>OnUnitInactiveSec=</varname></term>
+
+ <listitem><para>Defines monotonic timers relative to different
+ starting points: <varname>OnActiveSec=</varname> defines a
+ timer relative to the moment the timer itself is activated.
+ <varname>OnBootSec=</varname> defines a timer relative to when
+ the machine was booted up. <varname>OnStartupSec=</varname>
+ defines a timer relative to when systemd was first started.
+ <varname>OnUnitActiveSec=</varname> defines a timer relative
+ to when the unit the timer is activating was last activated.
+ <varname>OnUnitInactiveSec=</varname> defines a timer relative
+ to when the unit the timer is activating was last
+ deactivated.</para>
+
+ <para>Multiple directives may be combined of the same and of
+ different types. For example, by combining
+ <varname>OnBootSec=</varname> and
+ <varname>OnUnitActiveSec=</varname>, it is possible to define
+ a timer that elapses in regular intervals and activates a
+ specific service each time.</para>
+
+ <para>The arguments to the directives are time spans
+ configured in seconds. Example: "OnBootSec=50" means 50s after
+ boot-up. The argument may also include time units. Example:
+ "OnBootSec=5h 30min" means 5 hours and 30 minutes after
+ boot-up. For details about the syntax of time spans, see
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
+ <para>If a timer configured with <varname>OnBootSec=</varname>
+ or <varname>OnStartupSec=</varname> is already in the past
+ when the timer unit is activated, it will immediately elapse
+ and the configured unit is started. This is not the case for
+ timers defined in the other directives.</para>
+
+ <para>These are monotonic timers, independent of wall-clock
+ time and timezones. If the computer is temporarily suspended,
+ the monotonic clock stops too.</para>
+
+ <para>If the empty string is assigned to any of these options,
+ the list of timers is reset, and all prior assignments will
+ have no effect.</para>
+
+ <para>Note that timers do not necessarily expire at the
+ precise time configured with these settings, as they are
+ subject to the <varname>AccuracySec=</varname> setting
+ below.</para></listitem>
+
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>OnCalendar=</varname></term>
+
+ <listitem><para>Defines realtime (i.e. wallclock) timers with
+ calendar event expressions. See
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for more information on the syntax of calendar event
+ expressions. Otherwise, the semantics are similar to
+ <varname>OnActiveSec=</varname> and related settings.</para>
+
+ <para>Note that timers do not necessarily expire at the
+ precise time configured with this setting, as it is subject to
+ the <varname>AccuracySec=</varname> setting
+ below.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>AccuracySec=</varname></term>
+
+ <listitem><para>Specify the accuracy the timer shall elapse
+ with. Defaults to 1min. The timer is scheduled to elapse
+ within a time window starting with the time specified in
+ <varname>OnCalendar=</varname>,
+ <varname>OnActiveSec=</varname>,
+ <varname>OnBootSec=</varname>,
+ <varname>OnStartupSec=</varname>,
+ <varname>OnUnitActiveSec=</varname> or
+ <varname>OnUnitInactiveSec=</varname> and ending the time
+ configured with <varname>AccuracySec=</varname> later. Within
+ this time window, the expiry time will be placed at a
+ host-specific, randomized but stable position that is
+ synchronized between all local timer units. This is done in
+ order to distribute the wake-up time in networked
+ installations, as well as optimizing power consumption to
+ suppress unnecessary CPU wake-ups. To get best accuracy, set
+ this option to 1us. Note that the timer is still subject to
+ the timer slack configured via
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
+ <varname>TimerSlackNSec=</varname> setting. See
+ <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ for details. To optimize power consumption, make sure to set
+ this value as high as possible and as low as
+ necessary.</para></listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>Unit=</varname></term>
+
+ <listitem><para>The unit to activate when this timer elapses.
+ The argument is a unit name, whose suffix is not
+ <literal>.timer</literal>. If not specified, this value
+ defaults to a service that has the same name as the timer
+ unit, except for the suffix. (See above.) It is recommended
+ that the unit name that is activated and the unit name of the
+ timer unit are named identically, except for the
+ suffix.</para></listitem>
+ </varlistentry>
+
+
+ <varlistentry>
+ <term><varname>Persistent=</varname></term>
+
+ <listitem><para>Takes a boolean argument. If true, the time
+ when the service unit was last triggered is stored on disk.
+ When the timer is activated, the service unit is triggered
+ immediately if it would have been triggered at least once
+ during the time when the timer was inactive. This is useful to
+ catch up on missed runs of the service when the machine was
+ off. Note that this setting only has an effect on timers
+ configured with <varname>OnCalendar=</varname>.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>WakeSystem=</varname></term>
+
+ <listitem><para>Takes a boolean argument. If true, an elapsing
+ timer will cause the system to resume from suspend, should it
+ be suspended and if the system supports this. Note that this
+ option will only make sure the system resumes on the
+ appropriate times, it will not take care of suspending it
+ again after any work that is to be done is finished. Defaults
+ to <varname>false</varname>.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ </para>
+ </refsect1>
</refentry>
~ianmdlvl / elogind.git / blobdiff