Propane Smoker control using a servo?

I have ZERO experience, but woudl like to know if this is possible.

I have a propane smoker that I would like to automate the temp control a bit. So here is my idea.

Using a temp sensor inside the box the system turns the knob down when it is too hot and up when it is not hot enough. I'm thinking of attaching a RC type servo directly to the existing temp control knob. Is this doable? If so difficult?

It's been done