How do I set up watchdog performing specified action (eg. hard reset) of host when it becomes unresponsive (eg. kernel freezes)? Is there any form of virtualized /dev/watchdog?
While not exactly walking through the thing you need, you might want to take a look at this blog post https://www.vskilled.com/2015/11/automatically-reboot-an-esxi-host-after-psod/
You can modify the method described in there exactly to your needs. The variable you'd want to change would be "Misc.BlueScreenTimeout"
In order to answer this question, I just published the hardward watchdog VIB for you.
Hope this helps.