Editor’s note (Oct. 3, 2013): The information below is now deprecated. We recommend that you consult this documentation for ports info instead.
Is it 50030 or 50300 for that JobTracker UI? I can never remember!
Hadoop’s daemons expose a handful of ports over TCP. Some of these ports are used by Hadoop’s daemons to communicate amongst themselves (to schedule jobs, replicate blocks, etc.). Others ports are listening directly to users,