Terraform config for an EC2 instance with a replaceable EBS volume

userdata.sh

#!/bin/bash

DEVICE=/dev/$(lsblk -n | awk '$NF != "/" {print $1}')
FS_TYPE=$(file -s $DEVICE | awk '{print $2}')
MOUNT_POINT=/data

# If no FS, then this output contains "data"
if [ "$FS_TYPE" = "data" ]
then
    echo "Creating file system on $DEVICE"
    mkfs -t ext4 $DEVICE
fi

mkdir $MOUNT_POINT
mount $DEVICE $MOUNT_POINT

volumes.tf

resource "aws_ebs_volume" "test" {
    availability_zone = "eu-west-1a"
    size = 1
}

resource "template_file" "userdata" {
    filename = "userdata.sh"
}


resource "aws_instance" "test" {
    ami = "ami-be5cf7cd"
    availability_zone = "eu-west-1a"
    instance_type = "t1.micro"
    key_name = "${module.network.key_pair_id}"
    user_data = "${template_file.userdata.rendered}"
    tags {
        Name = "test-box"
    }
}

resource "aws_volume_attachment" "ebs_att" {
    device_name = "/dev/sdh"
    volume_id = "${aws_ebs_volume.test.id}"
    instance_id = "${aws_instance.test.id}"
}