I want to setup a hadoop-cluster in pseudo-distributed mode. I managed to perform all the setup-steps, including startuping a Namenode, Datanode, Jobtracker and a Tasktracke
I was getting the same issue and found that OpenSSH service was not running and it was causing the issue. After starting the SSH service it worked.
To check if SSH service is running or not:
ssh localhost
To start the service, if OpenSSH is already installed:
sudo /etc/init.d/ssh start