This doesn't seem possible, but it's occurred twice: services being started
on the wrong port. The bug is transient. I've discovered it when a
Tasktracker instance would not start and the TT log showed:
2012-12-03 18:45:55,729 ERROR org.apache.hadoop.mapred.TaskTracker: *Can
not start task tracker because java.net.BindException: Address already in
That is odd, so I look for the process that is holding the TT port with:
*fuser -n tcp 50060*
...and it shows a Regionserver process holding that port. I think it's
lying, perhaps the way CM starts the process wraps it in a misleading way?
However when I stop the Regionserver, the TT port is free and I can start
the TT as usual. It really appears that a Regionserver is being started on
a Tasktracker port.
Not sure what could be causing this but I've seen it twice recently. CM