myos/aws/register-image-device-mappings.json

[
    {
        "DeviceName": "/dev/sda1",
        "Ebs": {
            "SnapshotId": "${AWS_SNAP_ID}"
        }
    },
    {
        "DeviceName": "/dev/sdb",
        "VirtualName": "ephemeral0"
    }
]