Dominique Dumont
and 1 contributors

NAME

Config::Model::models::Systemd::Section::Timer - Configuration class Systemd::Section::Timer

DESCRIPTION

Configuration classes used by Config::Model

A unit configuration file whose name ends in .timer encodes information about a timer controlled and supervised by systemd, for timer-based activation.

This man page lists the configuration options specific to this unit type. See systemd.unit(5) 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.

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 foo.timer activates a matching service foo.service. The unit to activate may be controlled by Unit (see below).

Note that in case the unit to activate is already active at the time the timer elapses it is not restarted, but simply left running. There is no concept of spawning new service instances in this case. Due to this, services with RemainAfterExit set (which stay around continuously even after the service's main process exited) are usually not suitable for activation via repetitive timers, as they will only be activated once, and then stay around forever. This configuration class was generated from systemd documentation. by parse-man.pl

Elements

OnActiveSec

Defines monotonic timers relative to different starting points: OnActiveSec defines a timer relative to the moment the timer itself is activated. OnBootSec defines a timer relative to when the machine was booted up. OnStartupSec defines a timer relative to when systemd was first started. OnUnitActiveSec defines a timer relative to when the unit the timer is activating was last activated. OnUnitInactiveSec defines a timer relative to when the unit the timer is activating was last deactivated.

Multiple directives may be combined of the same and of different types. For example, by combining OnBootSec and OnUnitActiveSec, it is possible to define a timer that elapses in regular intervals and activates a specific service each time.

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 systemd.time(7).

If a timer configured with OnBootSec or OnStartupSec 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.

These are monotonic timers, independent of wall-clock time and timezones. If the computer is temporarily suspended, the monotonic clock stops too.

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.

Note that timers do not necessarily expire at the precise time configured with these settings, as they are subject to the AccuracySec setting below. Optional. Type uniline.

OnBootSec

Defines monotonic timers relative to different starting points: OnActiveSec defines a timer relative to the moment the timer itself is activated. OnBootSec defines a timer relative to when the machine was booted up. OnStartupSec defines a timer relative to when systemd was first started. OnUnitActiveSec defines a timer relative to when the unit the timer is activating was last activated. OnUnitInactiveSec defines a timer relative to when the unit the timer is activating was last deactivated.

Multiple directives may be combined of the same and of different types. For example, by combining OnBootSec and OnUnitActiveSec, it is possible to define a timer that elapses in regular intervals and activates a specific service each time.

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 systemd.time(7).

If a timer configured with OnBootSec or OnStartupSec 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.

These are monotonic timers, independent of wall-clock time and timezones. If the computer is temporarily suspended, the monotonic clock stops too.

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.

Note that timers do not necessarily expire at the precise time configured with these settings, as they are subject to the AccuracySec setting below. Optional. Type uniline.

OnStartupSec

Defines monotonic timers relative to different starting points: OnActiveSec defines a timer relative to the moment the timer itself is activated. OnBootSec defines a timer relative to when the machine was booted up. OnStartupSec defines a timer relative to when systemd was first started. OnUnitActiveSec defines a timer relative to when the unit the timer is activating was last activated. OnUnitInactiveSec defines a timer relative to when the unit the timer is activating was last deactivated.

Multiple directives may be combined of the same and of different types. For example, by combining OnBootSec and OnUnitActiveSec, it is possible to define a timer that elapses in regular intervals and activates a specific service each time.

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 systemd.time(7).

If a timer configured with OnBootSec or OnStartupSec 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.

These are monotonic timers, independent of wall-clock time and timezones. If the computer is temporarily suspended, the monotonic clock stops too.

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.

Note that timers do not necessarily expire at the precise time configured with these settings, as they are subject to the AccuracySec setting below. Optional. Type uniline.

OnUnitActiveSec

Defines monotonic timers relative to different starting points: OnActiveSec defines a timer relative to the moment the timer itself is activated. OnBootSec defines a timer relative to when the machine was booted up. OnStartupSec defines a timer relative to when systemd was first started. OnUnitActiveSec defines a timer relative to when the unit the timer is activating was last activated. OnUnitInactiveSec defines a timer relative to when the unit the timer is activating was last deactivated.

Multiple directives may be combined of the same and of different types. For example, by combining OnBootSec and OnUnitActiveSec, it is possible to define a timer that elapses in regular intervals and activates a specific service each time.

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 systemd.time(7).

If a timer configured with OnBootSec or OnStartupSec 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.

These are monotonic timers, independent of wall-clock time and timezones. If the computer is temporarily suspended, the monotonic clock stops too.

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.

Note that timers do not necessarily expire at the precise time configured with these settings, as they are subject to the AccuracySec setting below. Optional. Type uniline.

OnUnitInactiveSec

Defines monotonic timers relative to different starting points: OnActiveSec defines a timer relative to the moment the timer itself is activated. OnBootSec defines a timer relative to when the machine was booted up. OnStartupSec defines a timer relative to when systemd was first started. OnUnitActiveSec defines a timer relative to when the unit the timer is activating was last activated. OnUnitInactiveSec defines a timer relative to when the unit the timer is activating was last deactivated.

Multiple directives may be combined of the same and of different types. For example, by combining OnBootSec and OnUnitActiveSec, it is possible to define a timer that elapses in regular intervals and activates a specific service each time.

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 systemd.time(7).

If a timer configured with OnBootSec or OnStartupSec 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.

These are monotonic timers, independent of wall-clock time and timezones. If the computer is temporarily suspended, the monotonic clock stops too.

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.

Note that timers do not necessarily expire at the precise time configured with these settings, as they are subject to the AccuracySec setting below. Optional. Type uniline.

OnCalendar

Defines realtime (i.e. wallclock) timers with calendar event expressions. See systemd.time(7) for more information on the syntax of calendar event expressions. Otherwise, the semantics are similar to OnActiveSec and related settings.

Note that timers do not necessarily expire at the precise time configured with this setting, as it is subject to the AccuracySec setting below.

May be specified more than once. Optional. Type list of uniline.

AccuracySec

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 OnCalendar, OnActiveSec, OnBootSec, OnStartupSec, OnUnitActiveSec or OnUnitInactiveSec and ending the time configured with AccuracySec 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 optimize 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 systemd-system.conf(5)'s TimerSlackNSec setting. See prctl(2) for details. To optimize power consumption, make sure to set this value as high as possible and as low as necessary. Optional. Type uniline.

RandomizedDelaySec

Delay the timer by a randomly selected, evenly distributed amount of time between 0 and the specified time value. Defaults to 0, indicating that no randomized delay shall be applied. Each timer unit will determine this delay randomly each time it is started, and the delay will simply be added on top of the next determined elapsing time. This is useful to stretch dispatching of similarly configured timer events over a certain amount time, to avoid that they all fire at the same time, possibly resulting in resource congestion. Note the relation to AccuracySec above: the latter allows the service manager to coalesce timer events within a specified time range in order to minimize wakeups, the former does the opposite: it stretches timer events over a time range, to make it unlikely that they fire simultaneously. If RandomizedDelaySec and AccuracySec are used in conjunction, first the randomized delay is added, and then the result is possibly further shifted to coalesce it with other timer events happening on the system. As mentioned above AccuracySec defaults to 1min and RandomizedDelaySec to 0, thus encouraging coalescing of timer events. In order to optimally stretch timer events over a certain range of time, make sure to set RandomizedDelaySec to a higher value, and AccuracySec=1us. Optional. Type uniline.

Unit

The unit to activate when this timer elapses. The argument is a unit name, whose suffix is not .timer. 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. Optional. Type uniline.

Persistent

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 OnCalendar. Defaults to false. Optional. Type boolean.

WakeSystem

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 false. Optional. Type boolean.

RemainAfterElapse

Takes a boolean argument. If true, an elapsed timer will stay loaded, and its state remains queriable. If false, an elapsed timer unit that cannot elapse anymore is unloaded. Turning this off is particularly useful for transient timer units that shall disappear after they first elapse. Note that this setting has an effect on repeatedly starting a timer unit that only elapses once: if RemainAfterElapse is on, it will not be started again, and is guaranteed to elapse only once. However, if RemainAfterElapse is off, it might be started again if it is already elapsed, and thus be triggered multiple times. Defaults to yes. Optional. Type boolean.

SEE ALSO

COPYRIGHT

2010-2016 Lennart Poettering and others
2016 Dominique Dumont

LICENSE

LGPLv2.1+