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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COLOPHON |
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SYSTEMD.KILL(5) systemd.kill SYSTEMD.KILL(5)
systemd.kill - Process killing procedure configuration
service.service, socket.socket, mount.mount, swap.swap,
scope.scope
Unit configuration files for services, sockets, mount points, swap
devices and scopes share a subset of configuration options which
define the killing procedure of processes belonging to the unit.
This man page lists the configuration options shared by these five
unit types. See systemd.unit(5) for the common options shared by
all unit configuration files, and systemd.service(5),
systemd.socket(5), systemd.swap(5), systemd.mount(5) and
systemd.scope(5) for more information on the configuration file
options specific to each unit type.
The kill procedure configuration options are configured in the
[Service], [Socket], [Mount] or [Swap] section, depending on the
unit type.
KillMode=
Specifies how processes of this unit shall be killed. One of
control-group, mixed, process, none.
If set to control-group, all remaining processes in the
control group of this unit will be killed on unit stop (for
services: after the stop command is executed, as configured
with ExecStop=). If set to mixed, the SIGTERM signal (see
below) is sent to the main process while the subsequent
SIGKILL signal (see below) is sent to all remaining processes
of the unit's control group. If set to process, only the main
process itself is killed (not recommended!). If set to none,
no process is killed (strongly recommended against!). In this
case, only the stop command will be executed on unit stop, but
no process will be killed otherwise. Processes remaining alive
after stop are left in their control group and the control
group continues to exist after stop unless empty.
Note that it is not recommended to set KillMode= to process or
even none, as this allows processes to escape the service
manager's lifecycle and resource management, and to remain
running even while their service is considered stopped and is
assumed to not consume any resources.
Processes will first be terminated via SIGTERM (unless the
signal to send is changed via KillSignal= or
RestartKillSignal=). Optionally, this is immediately followed
by a SIGHUP (if enabled with SendSIGHUP=). If processes still
remain after:
• the main process of a unit has exited (applies to
KillMode=: mixed)
• the delay configured via the TimeoutStopSec= has passed
(applies to KillMode=: control-group, mixed, process)
the termination request is repeated with the SIGKILL signal or
the signal specified via FinalKillSignal= (unless this is
disabled via the SendSIGKILL= option). See kill(2) for more
information.
Defaults to control-group.
Added in version 187.
KillSignal=
Specifies which signal to use when stopping a service. This
controls the signal that is sent as first step of shutting
down a unit (see above), and is usually followed by SIGKILL
(see above and below). For a list of valid signals, see
signal(7). Defaults to SIGTERM.
Note that, right after sending the signal specified in this
setting, systemd will always send SIGCONT, to ensure that even
suspended tasks can be terminated cleanly.
Added in version 187.
RestartKillSignal=
Specifies which signal to use when restarting a service. The
same as KillSignal= described above, with the exception that
this setting is used in a restart job. Not set by default, and
the value of KillSignal= is used.
Added in version 244.
SendSIGHUP=
Specifies whether to send SIGHUP to remaining processes
immediately after sending the signal configured with
KillSignal=. This is useful to indicate to shells and
shell-like programs that their connection has been severed.
Takes a boolean value. Defaults to "no".
Added in version 207.
SendSIGKILL=
Specifies whether to send SIGKILL (or the signal specified by
FinalKillSignal=) to remaining processes after a timeout, if
the normal shutdown procedure left processes of the service
around. When disabled, a KillMode= of control-group or mixed
service will not restart if processes from prior services
exist within the control group. Takes a boolean value.
Defaults to "yes".
Added in version 187.
FinalKillSignal=
Specifies which signal to send to remaining processes after a
timeout if SendSIGKILL= is enabled. The signal configured here
should be one that is not typically caught and processed by
services (SIGTERM is not suitable). Developers can find it
useful to use this to generate a coredump to troubleshoot why
a service did not terminate upon receiving the initial SIGTERM
signal. This can be achieved by configuring LimitCORE= and
setting FinalKillSignal= to either SIGQUIT or SIGABRT.
Defaults to SIGKILL.
Added in version 240.
WatchdogSignal=
Specifies which signal to use to terminate the service when
the watchdog timeout expires (enabled through WatchdogSec=).
Defaults to SIGABRT.
Added in version 240.
systemd(1), systemctl(1), journalctl(1), systemd.unit(5),
systemd.service(5), systemd.socket(5), systemd.swap(5),
systemd.mount(5), systemd.exec(5), systemd.directives(7), kill(2),
signal(7)
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SYSTEMD.KILL(5)
Pages that refer to this page: systemd-run(1), systemd.automount(5), systemd.exec(5), systemd.mount(5), systemd.path(5), systemd.scope(5), systemd.service(5), systemd.socket(5), systemd.swap(5), systemd.timer(5), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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