Installing and configuring the Watchdog

*Watchdog timer ** - A hardware-implemented system hang-up control scheme. It is a timer that is periodically reset by the monitored system. If it is not reset within a certain period of time, the system is forced to reboot. In some cases the watchdog can send a signal to the system to reboot ("soft" reboot), in other cases the reboot is done by hardware (by closing the signal wire RST or similar).

Installation in Linux Ubuntu/Debian:

sudo apt-get install watchdog

A list of some of the files that will be installed on the system:

• /etc/init.d/watchdog
• /etc/init.d/wd_keepalive
• /etc/watchdog.conf
• /etc/default/watchdog
• /dev/watchdog
• /usr/sbin/watchdog
• /usr/sbin/wd_identify
• /usr/sbin/wd_keepalive
• /usr/share/doc/watchdog/
• /usr/share/man/man5/watchdog.conf.5.gz
• /usr/share/man/man8/watchdog.8.gz
• /usr/share/man/man8/wd_identify.8.gz
• /usr/share/man/man8/wd_keepalive.8.gz

Possible config parameters for /etc/watchdog.conf:

interval = 

Interval between two write operations to the watchdog. The default value is 10 seconds. An interval longer than a minute can only be used with the -f parameter from the command line.

logtick = 

If you write logs, you can skip recording events every specified number of intervals. For example, if logtick = 60 and interval 10, you get 600 seconds, so there will be no more than one entry in the log file every 10 minutes.

max-load-1 = 

The maximum allowed value of system load for 1 minute, above which the system will restart. 0 - disables the check.

max-load-5 = 

The maximum allowed value of system load for 5 minutes, above which the system will restart. 0 - disables the check.

max-load-15 = 

The maximum allowed value of system load for 15 minutes, above which the system will restart. 0 - disables the check.

min-memory = 

Set the minimum amount of virtual memory which must be free. 0 - check disabled.

max-temperature = 

Set the maximum temperature allowed.

watchdog-device = 

Setting the device name.

temperature-device = 

Setting the temperature device name.

file = 

File mode, file check.

change = 

Time interval for file mode.

pidfile = 

The name of the pid file. You can add a monitored process, for example "pidfile = /var/run/apache2.pid". If the process cannot be started, watchdog will constantly reboot the system.

ping = 

Ping mode, to check network connections. The option can be used more than once.

interface = 

Set the name of the network interface.

test-binary = 

Running a user test.

test-timeout = 

The test can run the specified number of seconds. 0 - unlimited.

repair-binary = 

Executed when the system cannot be rebooted.

admin = 

Email address for notifications, you can leave the value blank to disable.

realtime = 

Yes to make it impossible to unload watchdog from RAM.

priority = 

Set the priority for realtime mode.

Example setting with Intel TCO Watchog Timer. Module load:

sudo modprobe iTCO_wdt

In /etc/watchdog.conf it must be edited/added:

watchdog-device = /dev/watchdog
interval = 10

In /etc/default/watchdog specify the module name:

watchdog_module="iTCO_wdt"

You can add a debug option so that debugging information is written to the syslog:

watchdog_options="-v"

Restarting watchdog:

sudo /etc/init.d/watchdog restart

You can monitor real-time syslog entries with a command:

tail -f /var/log/syslog