| SYSTEMD.KILL(5) | systemd.kill | SYSTEMD.KILL(5) |
.SH "NAME" systemd.kill - Process killing procedure
configuration
.SH "SYNOPSIS"
.PP service.service, socket.socket, mount.mount,
swap.swap, scope.scope
.SH "DESCRIPTION"
.PP 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.
.PP 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.
.PP The kill procedure configuration options are configured in the [Service],
[Socket], [Mount] or [Swap] section, depending on the unit type.
.SH "OPTIONS"
.PP 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:
.sp 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.
.RE
.PP 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.
.RE
.PP 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.
.RE
.PP 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.
.RE
.PP 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.
.RE
.PP 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.
.RE
.PP 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.
.RE
.SH "SEE ALSO"
.PP 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)
| systemd 262.2 |