Hey @rxin I patched this to do a simpler check. Now that we require URI's for cluster schedulers it should work.

There is a minor failure mode where someone is running the very old (and completely undocumented) master format of just putting the host:port of the master to mean a mesos cluster, and their cluster also happens to have "local" in the first four names of the master hostname. Since this is so obscure, and the consequence is just that this helpful warning might not get shown, I'd prefer the simpler check.