It's short for "What's good in your life? "

"What's good" is more of a slang phrase. It's just like "what's up" or "how's it going." It's more common in the more urban areas of the United States.

thanks a lot

"What's good?" is sometimes used as a greeting now. It's the same as "What's up?" or "How's it going?" It's slang and a lot of people don't say it and won't understand it. It is nice to know what this means but I don't recommend actually saying it because it is still so rare.

Your question is very unclear. Can you give an example of how "what's good" is being used? That would help us understand the context.