Host watchdog gives Oracle ILOM the ability to perform user-settable predefined actions when Oracle ILOM notices that the host has stopped responding.
You can control the host watchdog parameters using the ilomconfig command, or by editing the HMP Watchdog Agent's configuration file.
Host watchdog is built on top of standard IPMI watchdog timer functionality. The HMP Watchdog Agent interacts with the IPMI watchdog timer as follows:
When the host watchdog is enabled by the user, it first checks to see if IPMI watchdog timer is already started. If the IPMI watchdog timer is started, host watchdog issues a log message, indicating that watchdog timer is already started and host watchdog remains in the Disable state.
This addresses the case where someone has already set the IPMI watchdog timer.
While the host watchdog is enabled, it periodically resets the IPMI watchdog timer to the configuration values of host watchdog.
This addresses the case where someone changes the configuration outside of HMP Watchdog Agent.
The host watchdog periodically resets the IPMI watchdog timer. When the OS hangs, and therefore the IPMI watchdog timer is not reset before the timer expires, Oracle ILOM performs the action specified by the Timer Action parameter.
See Host Watchdog Parameters for more information on the host watchdog parameters that can be modified.