#! /bin/bash

############################
# Launch this script as a current $user in the current node $cn to configure passwordless ssh to-and-fro $cn and the remote node $rn for the $user who execute this script.
# Assumption: The $user has already existed in the $rn and $cn nodes.
# The default values for $cn, $rn, $user are defined as
cn=10.192.1.10
rn=10.192.1.21
userhome=$(echo $HOME)
user=$(echo $USER)
############################

#### Modify the following variables, $cn, $rn to suit your case
cn=10.192.1.10   ### ur current node IP
rn=10.192.1.21	 ### the IP for remote node
#### end of Modify the following variables, $cn, $rn and $user to suit your case

#1a
## generates two files, id_rsa and id_rsa.pub, in /share/home/$user/.ssh in the current compute node
if [[ -e $userhome/.ssh/id_rsa.pub ]]; then echo "pub rsa exists. Will not creat any."; else ssh-keygen -t rsa; fi

### 1b copy the rsa key of the $user in the current node to the remote node
	ssh-copy-id -i $userhome/.ssh/id_rsa.pub $rn

### 2a remotely generates the rsa key for the $user in the rn by ssh-ing from the current compute node.
	ssh $user@$rn "if [[ -e $userhome/.ssh/id_rsa.pub ]]; then  echo "pub rsa exists. Will not creat any"; else ssh-keygen -t rsa; fi"

### 2b remotely asks the rsa key for the $user in the rn to be copied via ssh to the current compute node. 
	ssh $user@$rn "ssh-copy-id -i $userhome/.ssh/id_rsa.pub $HOSTNAME"