Determining if ephemeral storage is attached to an instance in Amazon Web Services console?

On any ec2 instance you can call an http service to query for the instance details, e.g. to see attached block devices mapping:

curl http://169.254.169.254/latest/meta-data/block-device-mapping/

to see details about a specific device:

curl http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral2

You will get the mapping of this device, e.g.: /dev/xvdb


Look in /etc/cloud/cloud.cfg - the ephemeral should be listed there like:

mounts:
 - [ ephemeral0, /media/ephemeral0, auto, "defaults" ]
 - [ swap, none, swap, sw, "0", "0" ]

Then in /etc/fstab you should see an entry like:

/dev/sda2   /media/ephemeral0   auto    defaults,comment=cloudconfig    0   2