I'm sure they do - but again google is probably holding a proprietary alternative to virtually every piece of software in the world :) Most of it is too tied to "the google way" to be useful to anybody else.

This is more true than the idea that there's a competitive advantage. We would love to open-source more of our stack (and are working towards it), but it's all very tied to the rest of our cluster environment. Piece by piece.

As an ex-googler I agree. Much if it just wouldn't be useful as is to most people as it's an environment that few match in load, resources, and diversity of services. Plus it's all integrated tightly across the board.