I don't know anything about MR in particular, but the open-sourcing process at Google often gets bogged down by how interconnected the codebase and ecosystem ar

I don't know anything about MR in particular, but the open-sourcing process at Google often gets bogged down by how interconnected the codebase and ecosystem are. Releasing an open source version of a component means reimplementing a lot of stuff that Google isn't ready to release yet but that that component depends on. Look at Bazel/Blaze - it took them a long time to get it out, and the open version doesn't have feature parity. Also take a look at their governance plan going forward, which hints at the difficulties.[1] That said, I suspect a large part of the reason is that Google's MapReduce is highly optimized for running in a Google datacenter, and they're generally pretty tight-lipped about the real secret sauce in their infrastructure. [1]http://bazel.io/governance.html http://bazel.io/governance.html