Unable to load native-hadoop library for your platform… using builtin-java classes where applicable
Starting namenodes on [localhost]
localhost: ssh: connect to host localhost port 22: Connection refused
localhost: ssh: connect to host localhost port 22: Connection refused
Starting secondary namenodes [0.0.0.0]

Solution:
Go to your terminal and type below 2 lines
Step 1:

$ ssh-keygen -t dsa -P ” -f ~/.ssh/id_dsa
$ cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

Step 2:
Go to System Preferences and enable Remote Login under