WD_KEEPALIVE(8)WD_KEEPALIVE(8)NAMEwd_keepalive - a simplified software watchdog daemon
SYNOPSISwd_keepalive [-c filename|--config-file filename]
DESCRIPTION
This is a simplified version of the watchdog daemon. If configured so
it only opens
.IR /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 inter‐
rupts.
The wd_keepalive daemon can be stopped without causing a reboot if the
device /dev/watchdog is closed correctly, unless your kernel is com‐
piled 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 unnec‐
essary 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 mem‐
ory 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.
FILES
/dev/watchdog
The watchdog device.
/var/run/wd_keepalive.pid
The pid file of the running wd_keepalive.
SEE ALSOwatchdog.conf(5)watchdog(8)4th Berkeley Distribution January 2005 WD_KEEPALIVE(8)
