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WATCHDOGD(8)            FreeBSD System Manager's Manual           WATCHDOGD(8)

     watchdogd - watchdog daemon

     watchdogd [-dnSw] [--debug] [--softtimeout] [--softtimeout-action action]
               [--pretimeout timeout] [--pretimeout-action action] [-e cmd]
               [-I file] [-s sleep] [-t timeout] [-T script_timeout]

     The watchdogd utility interfaces with the kernel's watchdog facility to
     ensure that the system is in a working state.  If watchdogd is unable to
     interface with the kernel over a specific timeout, the kernel will take
     actions to assist in debugging or restarting the computer.

     If -e cmd is specified, watchdogd will attempt to execute this command
     with system(3), and only if the command returns with a zero exit code
     will the watchdog be reset.  If -e cmd is not specified, the daemon will
     perform a trivial file system check instead.

     The -n argument 'dry-run' will cause watchdog not to arm the system
     watchdog and instead only run the watchdog function and report on
     failures.  This is useful for developing new watchdogd scripts as the
     system will not reboot if there are problems with the script.

     The -s sleep argument can be used to control the sleep period between
     each execution of the check and defaults to one second.

     The -t timeout specifies the desired timeout period in seconds.  The
     default timeout is 16 seconds.

     One possible circumstance which will cause a watchdog timeout is an
     interrupt storm.  If this occurs, watchdogd will no longer execute and
     thus the kernel's watchdog routines will take action after a configurable

     The -T script_timeout specifies the threshold (in seconds) at which the
     watchdogd will complain that its script has run for too long.  If unset
     script_timeout defaults to the value specified by the -s sleep option.

     Upon receiving the SIGTERM or SIGINT signals, watchdogd will first
     instruct the kernel to no longer perform watchdog checks and then will

     The watchdogd utility recognizes the following runtime options:

     -I file                         Write the process ID of the watchdogd
                                     utility in the specified file.

     -d --debug                      Do not fork.  When this option is
                                     specified, watchdogd will not fork into
                                     the background at startup.

     -S                              Do not send a message to the system
                                     logger when the watchdog command takes
                                     longer than expected to execute.  The
                                     default behaviour is to log a warning via
                                     the system logger with the LOG_DAEMON
                                     facility, and to output a warning to
                                     standard error.

     -w                              Complain when the watchdog script takes
                                     too long.  This flag will cause watchdogd
                                     to complain when the amount of time to
                                     execute the watchdog script exceeds the
                                     threshold of 'sleep' option.

     --pretimeout timeout            Set a "pretimeout" watchdog.  At
                                     "timeout" seconds before the watchdog
                                     will fire attempt an action.  The action
                                     is set by the --pretimeout-action flag.
                                     The default is just to log a message
                                     (WD_SOFT_LOG) via log(9).

     --pretimeout-action action      Set the timeout action for the
                                     pretimeout.  See the section Timeout

     --softtimeout                   Instead of arming the various hardware
                                     watchdogs, only use a basic software
                                     watchdog.  The default action is just to
                                     log(9) a message (WD_SOFT_LOG).

     --softtimeout-action action     Set the timeout action for the
                                     softtimeout.  See the section Timeout

Timeout Actions
     The following timeout actions are available via the --pretimeout-action
     and --softtimeout-action flags:

     panic         Call panic(9) when the timeout is reached.

     ddb           Enter the kernel debugger via kdb_enter(9) when the timeout
                   is reached.

     log           Log a message using log(9) when the timeout is reached.

     printf        call the kernel printf(9) to display a message to the
                   console and dmesg(8) buffer.

     Actions can be combined in a comma separated list as so: log,printf which
     would both printf(9) and log(9) which will send messages both to dmesg(8)
     and the kernel log(4) device for syslog(8).


   Debugging watchdogd and/or your watchdog script.
     This is a useful recipe for debugging watchdogd and your watchdog script.

     (Note that ^C works oddly because watchdogd calls system(3) so the first
     ^C will terminate the "sleep" command.)

     Explanation of options used:
           1.   Set Debug on (--debug)
           2.   Set the watchdog to trip at 30 seconds. (-t 30)
           3.   Use of a softtimeout:
                      1.   Use a softtimeout (do not arm the hardware
                           watchdog).  (--softtimeout)
                      2.   Set the softtimeout action to do both kernel
                           printf(9) and log(9) when it trips.
                           (--softtimeout-action log,printf)
           4.   Use of a pre-timeout:
                      1.   Set a pre-timeout of 15 seconds (this will later
                           trigger a panic/dump).  (--pretimeout 15)
                      2.   Set the action to also kernel printf(9) and log(9)
                           when it trips.  (--pretimeout-action log,printf)
           5.   Use of a script:
                      1.   Run "sleep 60" as a shell command that acts as the
                           watchdog (-e 'sleep 60')
                      2.   Warn us when the script takes longer than 1 second
                           to run (-w)

     watchdogd --debug -t 30 \
       --softtimeout --softtimeout-action log,printf \
       --pretimeout 15 --pretimeout-action log,printf \
       -e 'sleep 60' -w

   Production use of example
           1.   Set hard timeout to 120 seconds (-t 120)
           2.   Set a panic to happen at 60 seconds (to trigger a crash(8) for
                dump analysis):
                      1.   Use of pre-timeout (--pretimeout 60)
                      2.   Specify pre-timeout action (--pretimeout-action
                           log,printf,panic )
           3.   Use of a script:
                      1.   Run your script (-e '/path/to/your/script 60')
                      2.   Log if your script takes a longer than 15 seconds
                           to run time. (-w -T 15)

     watchdogd  -t 120 \
       --pretimeout 60 --pretimeout-action log,printf,panic \
       -e '/path/to/your/script 60' -w -T 15

     watchdog(4), watchdog(8), watchdog(9)

     The watchdogd utility appeared in FreeBSD 5.1.

     The watchdogd utility and manual page were written by Sean Kelly
     <> and Poul-Henning Kamp <>.

     Some contributions made by Jeff Roberson <>.

     The pretimeout and softtimeout action system was added by Alfred
     Perlstein <>.

FreeBSD 11.0-PRERELEASE          July 27, 2013         FreeBSD 11.0-PRERELEASE


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