Hadoop "Permission denied (publickey,password,keyboard-interactive)" warning

Proceed with the following steps:

1. Generate new keygen.

   ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
   

2. Register key gen:

   cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
   

Problem is when you are trying to ssh to a server (in this case localhost) it tries to authenticate you using your credential. And stores that info. But here password-less authentication is not configured, so each time you try to ssh, it will ask you for your password, which is a problem if machines try to communicate with each other using ssh. So to setup passwordless ssh, we need to add user machine's public key to server machines ~/.ssh/authorized_keys file. In this case, both the system are same machines.

So Long story short run the following command.

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys