A lot of users of Hadoop are companies with serious competition. If you took the time to figure all of this out, would you go post a howto for your competitors? No, might as well let them expend their own time and money to do what you did.

While that's not exactly the open source spirit, it is how plenty of people think and also happens to be the default, easiest thing to do. It would be nice if people could share to benefit themselves and each other.