DNS health probe configuration in NODE

NODE Level does not give me DNS option although there are other options to monitor like ICMP, TCP etc. Can you suggest any other way please ?

I see what you mean. Only a subset of monitors seems to be available to apply directly at the node level, and DNS isn't one of those. External monitor types look to be available though. You could potentially create an external monitor to run a dig against your node. This would probably be a considerable amount of effort though, if it's even feasible. I can think of no other way to accomplish it though, given your situation.

How do we setup external monitor ? could you brief me a bit please ? Cannt see that option under NODE so..

You'll have to go into Local Traffic -> Monitors and create it there. Then it should show under the node monitor configuration. The actual creation of the external monitor will be tricky. I've never configured an external monitor like this, so I don't know that I'll be of much help. We've created one to log into a node via SSH and run a script local to that device, but that's different than what you are attempting to do.

What language this script is required to run ? Can u give me a sample script of what you have ..if possible ? Thanks mate :)