##First create SSH keys. macOS Sierra includes newer version of openssl with more options over and above ssh-keygen
$ openssl genpkey -algorithm RSA -aes-256-cbc -outform PEM -out rancherkey.pem -pkeyopt rsa_keygen_bits:2048
...........+++
.......+++
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
$ ssh-keygen -y -f rancherkey.pem

$ diskutil list
/dev/disk6 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            RancherOS              *7.8 GB     disk6
$ diskutil unmountDisk /dev/disk6
Unmount of all volumes on disk6 was successful
$ sudo dd bs=1m if=/Users/damohox/Downloads/rancheros.iso of=/dev/rdisk6
Password:
54+0 records in
54+0 records out
56623104 bytes transferred in 17.959566 secs (3152810 bytes/sec)
$ sudo diskutil eject /dev/rdisk6


$ssh -i .ssh/miniranch.pem rancher@192.168.0.101
Enter passphrase for key '.ssh/miniranch.pem':
[rancher@rancher ~]$