Provided by: libconfig-model-systemd-perl_0.251.1-1_all 
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 <https://github.com/dod38fr/config-model-systemd/contrib/parse-man.pl>
Elements
OnActiveSec
Defines monotonic timers relative to different starting points:
Multiple directives may be combined of the same and of different types, in which case the
timer unit will trigger whenever any of the specified timer expressions elapse. 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. Moreover,
both monotonic time expressions and "OnCalendar" calendar expressions may be combined in
the same timer unit.
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 generally pauses, too. Note that if
"WakeSystem" is used, a different monotonic clock is selected that continues to advance
while the system is suspended and thus can be used as the trigger to resume the system.
If the empty string is assigned to any of these options, the list of timers is reset (both
monotonic timers and "OnCalendar" timers, see below), 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:
Multiple directives may be combined of the same and of different types, in which case the
timer unit will trigger whenever any of the specified timer expressions elapse. 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. Moreover,
both monotonic time expressions and "OnCalendar" calendar expressions may be combined in
the same timer unit.
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 generally pauses, too. Note that if
"WakeSystem" is used, a different monotonic clock is selected that continues to advance
while the system is suspended and thus can be used as the trigger to resume the system.
If the empty string is assigned to any of these options, the list of timers is reset (both
monotonic timers and "OnCalendar" timers, see below), 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:
Multiple directives may be combined of the same and of different types, in which case the
timer unit will trigger whenever any of the specified timer expressions elapse. 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. Moreover,
both monotonic time expressions and "OnCalendar" calendar expressions may be combined in
the same timer unit.
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 generally pauses, too. Note that if
"WakeSystem" is used, a different monotonic clock is selected that continues to advance
while the system is suspended and thus can be used as the trigger to resume the system.
If the empty string is assigned to any of these options, the list of timers is reset (both
monotonic timers and "OnCalendar" timers, see below), 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:
Multiple directives may be combined of the same and of different types, in which case the
timer unit will trigger whenever any of the specified timer expressions elapse. 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. Moreover,
both monotonic time expressions and "OnCalendar" calendar expressions may be combined in
the same timer unit.
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 generally pauses, too. Note that if
"WakeSystem" is used, a different monotonic clock is selected that continues to advance
while the system is suspended and thus can be used as the trigger to resume the system.
If the empty string is assigned to any of these options, the list of timers is reset (both
monotonic timers and "OnCalendar" timers, see below), 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:
Multiple directives may be combined of the same and of different types, in which case the
timer unit will trigger whenever any of the specified timer expressions elapse. 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. Moreover,
both monotonic time expressions and "OnCalendar" calendar expressions may be combined in
the same timer unit.
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 generally pauses, too. Note that if
"WakeSystem" is used, a different monotonic clock is selected that continues to advance
while the system is suspended and thus can be used as the trigger to resume the system.
If the empty string is assigned to any of these options, the list of timers is reset (both
monotonic timers and "OnCalendar" timers, see below), 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, in which case the timer unit will trigger whenever any of
the specified expressions elapse. Moreover calendar timers and monotonic timers (see
above) may be combined within the same timer unit.
If the empty string is assigned to any of these options, the list of timers is reset (both
"OnCalendar" timers and monotonic timers, see above), and all prior assignments will have
no effect. 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.
Note that this setting is primarily a power saving option that allows coalescing CPU wake-
ups. It should not be confused with "RandomizedDelaySec" (see below) which adds a random
value to the time the timer shall elapse next and whose purpose is the opposite: to
stretch elapsing of timer events over a longer period to reduce workload spikes. For
further details and explanations and how both settings play together, see below.
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 before each iteration, and
the delay will simply be added on top of the next determined elapsing time, unless
modified with "FixedRandomDelay", see below.
This setting is useful to stretch dispatching of similarly configured timer events over a
certain time interval, to prevent them from firing all 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, while
this setting does the opposite: it stretches timer events over an interval, 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 1 minute and "RandomizedDelaySec" to 0, thus
encouraging coalescing of timer events. In order to optimally stretch timer events over a
certain range of time, set "AccuracySec=1us" and "RandomizedDelaySec" to some higher
value. Optional. Type uniline.
FixedRandomDelay
Takes a boolean argument. When enabled, the randomized offset specified by
"RandomizedDelaySec" is reused for all firings of the same timer. For a given timer unit,
the offset depends on the machine ID, user identifier and timer name, which means that it
is stable between restarts of the manager. This effectively creates a fixed offset for an
individual timer, reducing the jitter in firings of this timer, while still avoiding
firing at the same time as other similarly configured timers.
This setting has no effect if "RandomizedDelaySec" is set to 0. Defaults to "false".
Optional. Type boolean.
OnClockChange
These options take boolean arguments. When true, the service unit will be triggered when
the system clock ("CLOCK_REALTIME") jumps relative to the monotonic clock
("CLOCK_MONOTONIC"), or when the local system timezone is modified. These options can be
used alone or in combination with other timer expressions (see above) within the same
timer unit. These options default to "false". Optional. Type uniline.
OnTimezoneChange
These options take boolean arguments. When true, the service unit will be triggered when
the system clock ("CLOCK_REALTIME") jumps relative to the monotonic clock
("CLOCK_MONOTONIC"), or when the local system timezone is modified. These options can be
used alone or in combination with other timer expressions (see above) within the same
timer unit. These options default to "false". 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.
Such triggering is nonetheless subject to the delay imposed by "RandomizedDelaySec". This
is useful to catch up on missed runs of the service when the system was powered down. Note
that this setting only has an effect on timers configured with "OnCalendar". Defaults to
"false".
Use systemctl clean --what=state X on the timer unit to remove the timestamp file
maintained by this option from disk. In particular, use this command before uninstalling a
timer unit. See systemctl(1) for details. 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".
Note that this functionality requires privileges and is thus generally only available in
the system service manager.
Note that behaviour of monotonic clock timers (as configured with "OnActiveSec",
"OnBootSec", "OnStartupSec", "OnUnitActiveSec", "OnUnitInactiveSec", see above) is altered
depending on this option. If false, a monotonic clock is used that is paused during system
suspend ("CLOCK_MONOTONIC"), if true a different monotonic clock is used that continues
advancing during system suspend ("CLOCK_BOOTTIME"), see clock_getres(2) for details.
Optional. Type boolean.
RemainAfterElapse
Takes a boolean argument. If true, a timer will stay loaded, and its state remains
queryable even after it elapsed and the associated unit (as configured with "Unit", see
above) deactivated again. If false, an elapsed timer unit that cannot elapse anymore is
unloaded once its associated unit deactivated again. Turning this off is particularly
useful for transient timer units. Note that this setting has an effect when repeatedly
starting a timer unit: if "RemainAfterElapse" is on, starting the timer a second time has
no effect. However, if "RemainAfterElapse" is off and the timer unit was already unloaded,
it can be started again, and thus the service can be triggered multiple times. Defaults to
"true". Optional. Type boolean.
SEE ALSO
• cme
COPYRIGHT
2010-2016 Lennart Poettering and others
2016 Dominique Dumont
LICENSE
LGPLv2.1+
perl v5.34.0 20Config::Model::models::Systemd::Section::Timer(3pm)