~$ SERVERIP=$(aws cloudformation describe-stacks --stack-name mystack \
   --query 'Stacks[*].Outputs' \
   | jq -r '.[0][0].OutputValue')
 
~$ ssh -i ~/.ssh/aws-key ubuntu@$SERVERIP
ubuntu@ip-172-31-45-1:~$ lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0   8G  0 disk 
└─xvda1 202:1    0   8G  0 part /
xvdd    202:48   0  80G  0 disk 
└─xvdd1 202:49   0  80G  0 part /mnt
