These will be attached when booting a new instance from your AMI. Your options here may vary depending on the type of VM you use. Example value: ``` json [{ "device_name":"xvda", "delete_on_termination":true, "volume_type":"gp2" }] ``` Documentation for Block Devices Mappings can be found here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html