AWS NVMe user data to add to /etc/fstab

user_data.sh

#!/bin/bash
## nvme to fstab blkid
##
##
## Disk mapping:
## Cassandra commitlog: /dev/sdb 
## Cassandra data: /dev/sdc
##
######################################

apt update 
apt install -y nvme-cli

BOOT=$(sudo blkid | grep nvme | grep -w cloudimg-rootfs | awk '{print $1}' | cut -d':' -f1)
DATA_DISKS=$(sudo fdisk -l | grep nvme | grep -v $BOOT | awk '{print $2}' | cut -d':' -f1)

mkdir -p /cassandra-commitlog /cassandra-data
cp /etc/fstab /etc/fstab.ORIG

function set_mount_efstab() {
  echo "checking disk $1 with aws mount $2"
  disk_id=$(blkid $1 | awk '{print $2}' | tr -d  "\"")
  case $2 in
    sdb)
      echo "setting commitlog to disk $1 with mount $2"
      echo "$disk_id  /cassandra-commitlog  xfs defaults,auto,noatime,noexec,nodiratime 0	0" >> /etc/fstab
      ;;
    sdc)
      echo "setting data to disk $1 with mount $2"
      echo "$disk_id  /cassandra-data  xfs defaults,auto,noatime,noexec,nodiratime 0	0" >> /etc/fstab
      ;;
    *)
      echo "failed to set disk $1 with aws_mount $2"
      ;;
  esac
}

for disk in $DATA_DISKS; do
  # Format disk
  mkfs.xfs -f $disk
  # Locate aws mount
  aws_mount=$(nvme id-ctrl --raw-binary $disk | cut -c3073-3104 | tr -s ' ')
  # setting fstabl
  set_mount_efstab $disk $aws_mount
done

mount -a