Establish SSH equivalence for RAC – do this on both side from the unix user you are installing from – in my case “oracle”
mkdir ~/.ssh
chmod 700 ~/.ssh
cd ~/.ssh
ssh-keygen -t rsa
ssh-keygen -t dsa
cat *.pub >> authorized_keys
scp authorized_keys rac2:/home/oracle/.ssh/
or use oracle 12.2 ssh setup wizard – a lot easier