Watchdog for Raspberry PI 2

I try to enable watchdog on PI2 to automatic restart when system hang. I followed the instruction from:
https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=100594
Doesn’t seems to work.
Help pls. I am setting remote for PI2 and I will not be able to restart on site when the PI2 hang.

No chkconfig for Ubuntu Mate…
No response from the community…