56f1136b_Hadoop_Troubleshooting__Possible_Problem
[Symptom] You get an error that "remote host identification has changed" when you try to ssh to localhost. [Possible Solution] You can ask your login to skip checking the validity of localhost. You do this by setting NoHostAuthenticationForLocalhost to yes in ~/.ssh/config. You can accomplish this with the following command: echo "NoHostAuthenticationForLocalhost yes" >>~/.ssh/config [Possible Problem] 
You have moved your single node cluster from one machine in the Berry Patch to another. The name localhost thus is pointing to a new machine, and your ssh client thinks that it might be a man-in-the-middle attack.
Hadoop Troubleshooting
Possible Problem