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NAME

       systemd.service - Service unit configuration

SYNOPSIS

       service.service

DESCRIPTION

       A unit configuration file whose name ends in .service encodes
       information about a process controlled and supervised by systemd.

       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 service specific
       configuration options are configured in the "[Service]" section.

       Additional options are listed in systemd.exec(5), which define the
       execution environment the commands are executed in, and in
       systemd.kill(5), which define the way the processes of the service are
       terminated, and in systemd.resource-control(5), which configure
       resource control settings for the processes of the service.

       Unless DefaultDependencies= is set to false, service units will
       implicitly have dependencies of type Requires= and After= on
       basic.target as well as dependencies of type Conflicts= and Before= on
       shutdown.target. These ensure that normal service units pull in basic
       system initialization, and are terminated cleanly prior to system
       shutdown. Only services involved with early boot or late system
       shutdown should disable this option.

       If a service is requested under a certain name but no unit
       configuration file is found, systemd looks for a SysV init script by
       the same name (with the .service suffix removed) and dynamically
       creates a service unit from that script. This is useful for
       compatibility with SysV. Note that this compatibility is quite
       comprehensive but not 100%. For details about the incompatibilities,
       see the Incompatibilities with SysV[1] document.

OPTIONS

       Service files must include a "[Service]" section, which carries
       information about the service and the process it supervises. A number
       of options that may be used in this section are shared with other unit
       types. These options are documented in systemd.exec(5) and
       systemd.kill(5). The options specific to the "[Service]" section of
       service units are the following:

       Type=
           Configures the process start-up type for this service unit. One of
           simple, forking, oneshot, dbus, notify or idle.

           If set to simple (the default value if neither Type= nor BusName=
           are specified), it is expected that the process configured with
           ExecStart= is the main process of the service. In this mode, if the
           process offers functionality to other processes on the system, its
           communication channels should be installed before the daemon is
           started up (e.g. sockets set up by systemd, via socket activation),
           as systemd will immediately proceed starting follow-up units.

           If set to forking, it is expected that the process configured with
           ExecStart= will call fork() as part of its start-up. The parent
           process is expected to exit when start-up is complete and all
           communication channels are set up. The child continues to run as
           the main daemon process. This is the behavior of traditional UNIX
           daemons. If this setting is used, it is recommended to also use the
           PIDFile= option, so that systemd can identify the main process of
           the daemon. systemd will proceed with starting follow-up units as
           soon as the parent process exits.

           Behavior of oneshot is similar to simple; however, it is expected
           that the process has to exit before systemd starts follow-up units.
           RemainAfterExit= is particularly useful for this type of service.

           Behavior of dbus is similar to simple; however, it is expected that
           the daemon acquires a name on the D-Bus bus, as configured by
           BusName=. systemd will proceed with starting follow-up units after
           the D-Bus bus name has been acquired. Service units with this
           option configured implicitly gain dependencies on the dbus.socket
           unit. This type is the default if BusName= is specified.

           Behavior of notify is similar to simple; however, it is expected
           that the daemon sends a notification message via sd_notify(3) or an
           equivalent call when it has finished starting up. systemd will
           proceed with starting follow-up units after this notification
           message has been sent. If this option is used, NotifyAccess= (see
           below) should be set to open access to the notification socket
           provided by systemd. If NotifyAccess= is not set, it will be
           implicitly set to main. Note that currently Type=notify will not
           work if used in combination with PrivateNetwork=yes.

           Behavior of idle is very similar to simple; however, actual
           execution of the service binary is delayed until all jobs are
           dispatched. This may be used to avoid interleaving of output of
           shell services with the status output on the console.

       RemainAfterExit=
           Takes a boolean value that specifies whether the service shall be
           considered active even when all its processes exited. Defaults to
           no.

       GuessMainPID=
           Takes a boolean value that specifies whether systemd should try to
           guess the main PID of a service if it cannot be determined
           reliably. This option is ignored unless Type=forking is set and
           PIDFile= is unset because for the other types or with an explicitly
           configured PID file, the main PID is always known. The guessing
           algorithm might come to incorrect conclusions if a daemon consists
           of more than one process. If the main PID cannot be determined,
           failure detection and automatic restarting of a service will not
           work reliably. Defaults to yes.

       PIDFile=
           Takes an absolute file name pointing to the PID file of this
           daemon. Use of this option is recommended for services where Type=
           is set to forking. systemd will read the PID of the main process of
           the daemon after start-up of the service. systemd will not write to
           the file configured here.

       BusName=
           Takes a D-Bus bus name that this service is reachable as. This
           option is mandatory for services where Type= is set to dbus, but
           its use is otherwise recommended if the process takes a name on the
           D-Bus bus.

       ExecStart=
           Commands with their arguments that are executed when this service
           is started. For each of the specified commands, the first argument
           must be an absolute and literal path to an executable.

           When Type is not oneshot, only one command may be given. When
           Type=oneshot is used, more than one command may be specified.
           Multiple command lines may be concatenated in a single directive by
           separating them with semicolons (these semicolons must be passed as
           separate words). Alternatively, this directive may be specified
           more than once with the same effect. Lone semicolons may be escaped
           as "\;". If the empty string is assigned to this option, the list
           of commands to start is reset, prior assignments of this option
           will have no effect.

           Each command line is split on whitespace, with the first item being
           the command to execute, and the subsequent items being the
           arguments. Double quotes ("...") and single quotes ('...') may be
           used, in which case everything until the next matching quote
           becomes part of the same argument. Quotes themselves are removed
           after parsing. In addition, a trailing backslash ("\") may be used
           to merge lines. This syntax is intended to be very similar to shell
           syntax, but only the meta-characters and expansions described in
           the following paragraphs are understood. Specifically, redirection
           using "<", "<<", ">", and ">>", pipes using "|", and running
           programs in the background using "&" and other elements of shell
           syntax are not supported.

           If more than one command is specified, the commands are invoked
           sequentially in the order they appear in the unit file. If one of
           the commands fails (and is not prefixed with "-"), other lines are
           not executed, and the unit is considered failed.

           Unless Type=forking is set, the process started via this command
           line will be considered the main process of the daemon.

           The command line accepts "%" specifiers as described in
           systemd.unit(5). Note that the first argument of the command line
           (i.e. the program to execute) may not include specifiers.

           Basic environment variable substitution is supported. Use "${FOO}"
           as part of a word, or as a word of its own, on the command line, in
           which case it will be replaced by the value of the environment
           variable including all whitespace it contains, resulting in a
           single argument. Use "$FOO" as a separate word on the command line,
           in which case it will be replaced by the value of the environment
           variable split at whitespace, resulting in zero or more arguments.
           To pass a literal dollar sign, use "$$". Variables whose value is
           not known at expansion time are treated as empty strings. Note that
           the first argument (i.e. the program to execute) may not be a
           variable.

           Variables to be used in this fashion may be defined through
           Environment= and EnvironmentFile=. In addition, variables listed in
           the section "Environment variables in spawned processes" in
           systemd.exec(5), which are considered "static configuration", may
           be used (this includes e.g.  $USER, but not $TERM).

           Optionally, if the absolute file name is prefixed with "@", the
           second token will be passed as "argv[0]" to the executed process,
           followed by the further arguments specified. If the absolute
           filename is prefixed with "-", an exit code of the command normally
           considered a failure (i.e. non-zero exit status or abnormal exit
           due to signal) is ignored and considered success. If both "-" and
           "@" are used, they can appear in either order.

           Note that this setting does not directly support shell command
           lines. If shell command lines are to be used, they need to be
           passed explicitly to a shell implementation of some kind. Example:

               ExecStart=/bin/sh -c 'dmesg | tac'

           Example:

               ExecStart=/bin/echo one ; /bin/echo "two two"

           This will execute /bin/echo two times, each time with one argument:
           "one" and "two two", respectively. Because two commands are
           specified, Type=oneshot must be used.

           Example:

               ExecStart=/bin/echo / >/dev/null & \; \
               /bin/ls

           This will execute /bin/echo with five arguments: "/", ">/dev/null",
           "&", ";", and "/bin/ls".

           Example:

               Environment="ONE=one" 'TWO=two two'
               ExecStart=/bin/echo $ONE $TWO ${TWO}

           This will execute /bin/echo with four arguments: "one", "two",
           "two", and "two two".

       ExecStartPre=, ExecStartPost=
           Additional commands that are executed before or after the command
           in ExecStart=, respectively. Syntax is the same as for ExecStart=,
           except that multiple command lines are allowed and the commands are
           executed one after the other, serially.

           If any of those commands (not prefixed with "-") fail, the rest are
           not executed and the unit is considered failed.

       ExecReload=
           Commands to execute to trigger a configuration reload in the
           service. This argument takes multiple command lines, following the
           same scheme as described for ExecStart= above. Use of this setting
           is optional. Specifier and environment variable substitution is
           supported here following the same scheme as for ExecStart=.

           One additional, special environment variable is set: if known,
           $MAINPID is set to the main process of the daemon, and may be used
           for command lines like the following:

               /bin/kill -HUP $MAINPID

           Note however that reloading a daemon by sending a signal (as with
           the example line above) is usually not a good choice, because this
           is an asynchronous operation and hence not suitable to order
           reloads of multiple services against each other. It is strongly
           recommended to set ExecReload= to a command that no only triggers a
           configuration reload of the daemon, but also synchronously waits
           for it complete.

       ExecStop=
           Commands to execute to stop the service started via ExecStart=.
           This argument takes multiple command lines, following the same
           scheme as described for ExecStart= above. Use of this setting is
           optional. After the commands configured in this option are run, all
           processes remaining for a service are terminated according to the
           KillMode= setting (see systemd.kill(5)). If this option is not
           specified, the process is terminated immediately when service stop
           is requested. Specifier and environment variable substitution is
           supported (including $MAINPID, see above).

       ExecStopPost=
           Additional commands that are executed after the service was
           stopped. This includes cases where the commands configured in
           ExecStop= were used, where the service does not have any ExecStop=
           defined, or where the service exited unexpectedly. This argument
           takes multiple command lines, following the same scheme as
           described for ExecStart. Use of these settings is optional.
           Specifier and environment variable substitution is supported.

       RestartSec=
           Configures the time to sleep before restarting a service (as
           configured with Restart=). Takes a unit-less value in seconds, or a
           time span value such as "5min 20s". Defaults to 100ms.

       TimeoutStartSec=
           Configures the time to wait for start-up. If a daemon service does
           not signal start-up completion within the configured time, the
           service will be considered failed and will be shut down again.
           Takes a unit-less value in seconds, or a time span value such as
           "5min 20s". Pass "0" to disable the timeout logic. Defaults to
           TimeoutStartSec= from the manager configuration file, except when
           Type=oneshot is used, in which case the timeout is disabled by
           default.

       TimeoutStopSec=
           Configures the time to wait for stop. If a service is asked to
           stop, but does not terminate in the specified time, it will be
           terminated forcibly via SIGTERM, and after another timeout of equal
           duration with SIGKILL (see KillMode= in systemd.kill(5)). Takes a
           unit-less value in seconds, or a time span value such as "5min
           20s". Pass "0" to disable the timeout logic. Defaults to
           TimeoutStartSec= from the manager configuration file.

       TimeoutSec=
           A shorthand for configuring both TimeoutStartSec= and
           TimeoutStopSec= to the specified value.

       WatchdogSec=
           Configures the watchdog timeout for a service. The watchdog is
           activated when the start-up is completed. The service must call
           sd_notify(3) regularly with "WATCHDOG=1" (i.e. the "keep-alive
           ping"). If the time between two such calls is larger than the
           configured time, then the service is placed in a failed state. By
           setting Restart= to on-failure or always, the service will be
           automatically restarted. The time configured here will be passed to
           the executed service process in the WATCHDOG_USEC= environment
           variable. This allows daemons to automatically enable the
           keep-alive pinging logic if watchdog support is enabled for the
           service. If this option is used, NotifyAccess= (see below) should
           be set to open access to the notification socket provided by
           systemd. If NotifyAccess= is not set, it will be implicitly set to
           main. Defaults to 0, which disables this feature.

       Restart=
           Configures whether the service shall be restarted when the service
           process exits, is killed, or a timeout is reached. The service
           process may be the main service process, but it may also be one of
           the processes specified with ExecStartPre=, ExecStartPost=,
           ExecStop=, ExecStopPost=, or ExecReload=. When the death of the
           process is a result of systemd operation (e.g. service stop or
           restart), the service will not be restarted. Timeouts include
           missing the watchdog "keep-alive ping" deadline and a service
           start, reload, and stop operation timeouts.

           Takes one of no, on-success, on-failure, on-watchdog, on-abort, or
           always. If set to no (the default), the service will not be
           restarted. If set to on-success, it will be restarted only when the
           service process exits cleanly. In this context, a clean exit means
           an exit code of 0, or one of the signals SIGHUP, SIGINT, SIGTERM,
           or SIGPIPE, and additionally, exit statuses and signals specified
           in SuccessExitStatus=. If set to on-failure, the service will be
           restarted when the process exits with a non-zero exit code, is
           terminated by a signal (including on core dump), when an operation
           (such as service reload) times out, and when the configured
           watchdog timeout is triggered. If set to on-abort, the service will
           be restarted only if the service process exits due to an uncaught
           signal not specified as a clean exit status. If set to on-watchdog,
           the service will be restarted only if the watchdog timeout for the
           service expires. If set to always, the service will be restarted
           regardless of whether it exited cleanly or not, got terminated
           abnormally by a signal, or hit a timeout.

           In addition to the above settings, the service will not be
           restarted if the exit code or signal is specified in
           RestartPreventExitStatus= (see below).

       SuccessExitStatus=
           Takes a list of exit status definitions that when returned by the
           main service process will be considered successful termination, in
           addition to the normal successful exit code 0 and the signals
           SIGHUP, SIGINT, SIGTERM, and SIGPIPE. Exit status definitions can
           either be numeric exit codes or termination signal names, separated
           by spaces. For example:

               SuccessExitStatus=1 2 8 SIGKILL

           ensures that exit codes 1, 2, 8 and the termination signal SIGKILL
           are considered clean service terminations.

           Note that if a process has a signal handler installed and exits by
           calling _exit(2) in response to a signal, the information about the
           signal is lost. Programs should instead perform cleanup and kill
           themselves with the same signal instead. See Proper handling of

           This option may appear more than once, in which case the list of
           successful exit statuses is merged. If the empty string is assigned
           to this option, the list is reset, all prior assignments of this
           option will have no effect.

       RestartPreventExitStatus=
           Takes a list of exit status definitions that when returned by the
           main service process will prevent automatic service restarts,
           regardless of the restart setting configured with Restart=. Exit
           status definitions can either be numeric exit codes or termination
           signal names, and are separated by spaces. Defaults to the empty
           list, so that, by default, no exit status is excluded from the
           configured restart logic. Example: "RestartPreventExitStatus=1 6
           SIGABRT", ensures that exit codes 1 and 6 and the termination
           signal SIGABRT will not result in automatic service restarting.
           This option may appear more than once, in which case the list of
           restart-preventing statuses is merged. If the empty string is
           assigned to this option, the list is reset and all prior
           assignments of this option will have no effect.

       PermissionsStartOnly=
           Takes a boolean argument. If true, the permission-related execution
           options, as configured with User= and similar options (see
           systemd.exec(5) for more information), are only applied to the
           process started with ExecStart=, and not to the various other
           ExecStartPre=, ExecStartPost=, ExecReload=, ExecStop=, and
           ExecStopPost= commands. If false, the setting is applied to all
           configured commands the same way. Defaults to false.

       RootDirectoryStartOnly=
           Takes a boolean argument. If true, the root directory, as
           configured with the RootDirectory= option (see systemd.exec(5) for
           more information), is only applied to the process started with
           ExecStart=, and not to the various other ExecStartPre=,
           ExecStartPost=, ExecReload=, ExecStop=, and ExecStopPost= commands.
           If false, the setting is applied to all configured commands the
           same way. Defaults to false.

       NonBlocking=
           Set the O_NONBLOCK flag for all file descriptors passed via
           socket-based activation. If true, all file descriptors >= 3 (i.e.
           all except stdin, stdout, and stderr) will have the O_NONBLOCK flag
           set and hence are in non-blocking mode. This option is only useful
           in conjunction with a socket unit, as described in
           systemd.socket(5). Defaults to false.

       NotifyAccess=
           Controls access to the service status notification socket, as
           accessible via the sd_notify(3) call. Takes one of none (the
           default), main or all. If none, no daemon status updates are
           accepted from the service processes, all status update messages are
           ignored. If main, only service updates sent from the main process
           of the service are accepted. If all, all services updates from all
           members of the service's control group are accepted. This option
           should be set to open access to the notification socket when using
           Type=notify or WatchdogSec= (see above). If those options are used
           but NotifyAccess= is not configured, it will be implicitly set to
           main.

       Sockets=
           Specifies the name of the socket units this service shall inherit
           the sockets from when the service is started. Normally it should
           not be necessary to use this setting as all sockets whose unit
           shares the same name as the service (ignoring the different suffix
           of course) are passed to the spawned process.

           Note that the same socket may be passed to multiple processes at
           the same time. Also note that a different service may be activated
           on incoming traffic than that which inherits the sockets. Or in
           other words: the Service= setting of .socket units does not have to
           match the inverse of the Sockets= setting of the .service it refers
           to.

           This option may appear more than once, in which case the list of
           socket units is merged. If the empty string is assigned to this
           option, the list of sockets is reset, and all prior uses of this
           setting will have no effect.

       StartLimitInterval=, StartLimitBurst=
           Configure service start rate limiting. By default, services which
           are started more than 5 times within 10 seconds are not permitted
           to start any more times until the 10 second interval ends. With
           these two options, this rate limiting may be modified. Use
           StartLimitInterval= to configure the checking interval (defaults to
           DefaultStartLimitInterval= in manager configuration file, set to 0
           to disable any kind of rate limiting). Use StartLimitBurst= to
           configure how many starts per interval are allowed (defaults to
           DefaultStartLimitBurst= in manager configuration file). These
           configuration options are particularly useful in conjunction with
           Restart=; however, they apply to all kinds of starts (including
           manual), not just those triggered by the Restart= logic. Note that
           units which are configured for Restart= and which reach the start
           limit are not attempted to be restarted anymore; however, they may
           still be restarted manually at a later point, from which point on,
           the restart logic is again activated. Note that systemctl
           reset-failed will cause the restart rate counter for a service to
           be flushed, which is useful if the administrator wants to manually
           start a service and the start limit interferes with that.

       StartLimitAction=
           Configure the action to take if the rate limit configured with
           StartLimitInterval= and StartLimitBurst= is hit. Takes one of none,
           reboot, reboot-force, or reboot-immediate. If none is set, hitting
           the rate limit will trigger no action besides that the start will
           not be permitted.  reboot causes a reboot following the normal
           shutdown procedure (i.e. equivalent to systemctl reboot).
           reboot-force causes a forced reboot which will terminate all
           processes forcibly but should cause no dirty file systems on reboot
           (i.e. equivalent to systemctl reboot -f) and reboot-immediate
           causes immediate execution of the reboot(2) system call, which
           might result in data loss. Defaults to none.

       Check systemd.exec(5) and systemd.kill(5) for more settings.

COMPATIBILITY OPTIONS

       The following options are also available in the "[Service]" section,
       but exist purely for compatibility reasons and should not be used in
       newly written service files.

       SysVStartPriority=
           Set the SysV start priority to use to order this service in
           relation to SysV services lacking LSB headers. This option is only
           necessary to fix ordering in relation to legacy SysV services that
           have no ordering information encoded in the script headers. As
           such, it should only be used as a temporary compatibility option
           and should not be used in new unit files. Almost always, it is a
           better choice to add explicit ordering directives via After= or
           Before=, instead. For more details, see systemd.unit(5). If used,
           pass an integer value in the range 0-99.

       FsckPassNo=
           Set the fsck passno priority to use to order this service in
           relation to other file system checking services. This option is
           only necessary to fix ordering in relation to fsck jobs
           automatically created for all /etc/fstab entries with a value in
           the fs_passno column > 0. As such it should only be used as option
           for fsck services. Almost always it is a better choice to add
           explicit ordering directives via After= or Before=, instead. For
           more details see systemd.unit(5). If used, pass an integer value in
           the same range as /etc/fstab's fs_passno column. See fstab(5) for
           details.

SEE ALSO

       systemd(1), systemctl(8), systemd.unit(5), systemd.exec(5),
       systemd.resource-control(5), systemd.kill(5), systemd.directives(7)

NOTES

        1. Incompatibilities with SysV
           http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities

        2. Proper handling of SIGINT/SIGQUIT — How to be a proper program
           http://www.cons.org/cracauer/sigint.php



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