Configure Raid for AWS Instance (NVME Supported)

config_aws_raid.sh

#!/usr/bin/env bash

# ========================================================== configurations ===

RAID_NAME=ephemeral_raid
RAID_DEVICE=/dev/md0
RAID_MOUNT_PATH=/mnt/ephemeral

# =============================================================== functions ===

function list_instance_stores {
  if [[ -e /dev/nvme0n1 ]]; then
    # instance with nvme
    instance_stores=( $(nvme list | awk '/Instance Storage/ {print $1}') )
  else
    # instance without nvme
    BDMURL="http://169.254.169.254/latest/meta-data/block-device-mapping/"
    osdevice=$(sudo lsblk -o NAME -n | grep -v '[[:digit:]]' | sed "s/^sd/xvd/g")
    instance_stores=()
    for bd in $(curl -s "${BDMURL}"); do
      mapdevice=$(curl -s "${BDMURL}/${bd}/" | sed "s/^sd/xvd/g");
      if grep -wq "${mapdevice}" <<< "${osdevice}"; then
        instance_stores+=("${mapdevice}")
      fi
    done
  fi
  echo "${instance_stores[@]}"
}

function provision_instance_stores {
  devices=( $(list_instance_stores) )
  count=${#devices[@]}

  mkdir -p ${RAID_MOUNT_PATH}
  if [[ ${count} -eq 1 ]]; then
    # only 1 device so only format and mount
    mkfs.ext4 "${devices[1]}"
    echo "${devices[1]}" ${RAID_MOUNT_PATH} ext4 defaults,noatime 0 2 >> /etc/fstab
  elif [[ ${count} -gt 1 ]]; then
    # config raid 0, format, and mount
    mdadm --create --verbose --level=0 ${RAID_DEVICE} --auto=yes --name=${RAID_NAME} --raid-devices="${count}" "${devices[@]}"
    mdadm --wait ${RAID_DEVICE}
    mkfs.ext4 ${RAID_DEVICE}
    mdadm --detail --scan >> /etc/mdadm.conf
    dracut -H -f "/boot/initramfs-$(uname -r).img" "$(uname -r)"
    echo "${RAID_DEVICE} ${RAID_MOUNT_PATH} ext4 defaults,noatime 0 2" >> /etc/fstab
  fi
  mount -a
}

Simple script to RAID 0 the available ephemeral instance storage devices of a AWS EC2 instance.. It supports instances with or without NVME devices (e.g. Nitro instance types). If only one instance storage device is found, it will only format and mount.