This post will describe how to set passwordless SSH for master node and slave nodes.
First on master node, generate SSH key using below command,
Above command will generate id_rsa.pub key file in ~/.ssh/ directory.
Now copy this key to authorized_keys file on master and/or slave nodes
for master node,
Above command will prompt you password for slave node
Now test SSH with master and slave. It should not prompt you for password.
If you have just single node setup where master node is also a data node then just follow instructions for master node.