systemd.kill(5) — Linux manual page


SYSTEMD.KILL(5)               systemd.kill               SYSTEMD.KILL(5)

NAME         top

       systemd.kill - Process killing procedure configuration

SYNOPSIS         top

       service.service, socket.socket, mount.mount, swap.swap,

DESCRIPTION         top

       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

       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         top

           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

           Defaults to control-group.

           Added in version 187.

           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.

           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.

           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.

           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.

           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.

           Specifies which signal to use to terminate the service when
           the watchdog timeout expires (enabled through WatchdogSec=).
           Defaults to SIGABRT.

           Added in version 240.

SEE ALSO         top

       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)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨⟩.  If you have
       a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2023-12-22.)  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

systemd 255                                              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)