NAME

       wd_keepalive - a simplified software watchdog daemon

SYNOPSIS

       wd_keepalive [-c filename|--config-file filename]

DESCRIPTION

       This is a simplified version of the watchdog daemon. Unlike the full watchdog, this daemon
       run no tests and only serves to keep the hardware timer refreshed. Typically this is  used
       on  system  start-up to provide protection before the services that the full version tests
       are running, and on shutdown to continue the refresh while those services are stopped.

       If configured so it only opens /dev/watchdog, and keeps writing to it often enough to keep
       the  kernel  from  resetting,  at least once per minute. Each write delays the reboot time
       another minute. After a minute of inactivity the watchdog hardware will cause a reset.  In
       the  case  of  the software watchdog the ability to reboot will depend on the state of the
       machines and interrupts.

       The  wd_keepalive  daemon  can  be  stopped  without  causing  a  reboot  if  the   device
       /dev/watchdog   is   closed   correctly,   unless   your   kernel  is  compiled  with  the
       CONFIG_WATCHDOG_NOWAYOUT option enabled.

       Under high system load wd_keepalive might be swapped out of memory and may fail to make it
       back  in  in  time.  Under these circumstances the Linux kernel will reset the machine. To
       make sure you won't get unnecessary reboots make sure you have the variable  realtime  set
       to  yes  in  the  configuration  file  watchdog.conf.   This  adds  real  time  support to
       wd_keepalive: it will lock itself into memory and there should  be no problem  even  under
       the highest of loads.

       On  system  running  out  of  memory  the kernel will try to free enough memory by killing
       process. The wd_keepalive daemon itself is  exempted  from  this  so-called  out-of-memory
       killer.

OPTIONS

       Available command line options are the following:

       -c config-file, --config-file config-file
              Use    config-file   as   the   configuration   file   instead   of   the   default
              /etc/watchdog.conf.

       -X num, --loop-exit num
              Run for 'num' loops then exit as if SIG_TERM was received. Intended for  test/debug
              (e.g.  using  valgrind  for  checking memory access). If the daemon exits on a loop
              counter and you have the CONFIG_WATCHDOG_NOWAYOUT option compiled for the kernel or
              device-driver then an unplanned reboot will follow - be warned!

FILES

       /dev/watchdog
              The watchdog device.

       /var/run/wd_keepalive.pid
              The pid file of the running wd_keepalive.

SEE ALSO

       watchdog.conf(5)

       watchdog(8)