NAME
systemd.kill - Process killing procedure configurationSYNOPSIS
service.service, socket.socket, mount.mount, swap.swap, scope.scopeDESCRIPTION
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.OPTIONS
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 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.
KillSignal=
•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)
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.
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.
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".
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".
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.
WatchdogSignal=
Specifies which signal to use to terminate the
service when the watchdog timeout expires (enabled through
WatchdogSec=). Defaults to SIGABRT.
SEE ALSO
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 252 |