Detect and mount ephemeral storage

mount_ephemeral.sh

#!/bin/bash
set -e

function get_instance_storage_nvme() {
    for nvme_device_name in `lsblk | cut --delimiter=" " --fields=1 | grep ^nvme | sort -n`; do
        local nvme_device="/dev/${nvme_device_name}"
        if ( nvme id-ctrl "${nvme_device}" | grep --quiet "^mn\\s*:\\s*Amazon EC2 NVMe Instance Storage\\s*$" ); then
            echo "${nvme_device}"
        fi
    done
}

MOUNTPOINT=${1:-/ephemeral}
DEVICE=($(get_instance_storage_nvme))

echo "mountpoint for instance storage: $MOUNTPOINT"
echo "instance storage devices found: ${DEVICE[@]}"

if [ "${#DEVICE[@]}" -eq "0" ]; then
    echo "no instance storage devices available"
    exit 0
elif [ "${#DEVICE[@]}" -gt "1" ]; then
    echo "${#DEVICE[@]} storage devices available, creating RAID0"
    mdadm --create --level=0 /dev/md0 --verbose --raid-devices=${#DEVICE[@]} ${DEVICE[@]}
    DEVICE=/dev/md0
fi

mkfs -t ext4 -V $DEVICE

mkdir -p $MOUNTPOINT
mount $DEVICE $MOUNTPOINT