wd_keepalive - a simplified software watchdog daemon

       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.

/dev/watchdog
              The watchdog device.

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

       wd_keepalive - a simplified software watchdog daemon

       Available command line options are the following:

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

       -Xnum, --loop-exitnum
              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!

watchdog.conf(5)

       watchdog(8)

4th Berkeley Distribution                           June 2015                                    WD_KEEPALIVE(8)

wd_keepalive [-cfilename|--config-filefilename]