Config::Model::models::Systemd::Section::Timer - Configuration class
Systemd::Section::Timer
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>
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
- •
- cme
- 2010-2016 Lennart Poettering and others
- 2016 Dominique Dumont
- LGPLv2.1+