Monitors local disk space on EC2 instance and resizes volume when usage is above certain percentage. Filesystem and partition is available, too.

disk_space_monitor_and_resizer.sh

#!/bin/bash
#This script needs a bit of work. I would like to have the option to use xvd* or sd*.
#As of right now you can not use this script if you have sd* attachments or are using
#LVM.

#Set Alert percent and volume expansion increment in GiB
pcent=85
incr=500
#End Variables

instance=$(curl -s http://169.254.169.254/latest/meta-data/instance-id/)
df -TH | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $6 " " $1 " " $2 }' | while read output;
do
  echo $output
  usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1  )
  partition=$(echo $output | awk '{ print $2 }')
  raw=$(printf '%s\n' "${partition//[[:digit:]]/}")
  fs=$(echo $output | awk '{print $3}')
  ispart=$(parted $raw print | awk '/Partition\ Table/ {print $3}')
  if [ $usep -ge $pcent ]; then
    echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)..."
    echo "Attempting to resize the $partition volume"
    att=$(aws ec2 describe-volumes --query Volumes[*].[VolumeId,Attachments[0].Device,Attachments[0].InstanceId,Size] --output text | grep $instance | grep $raw)
    volume=$(echo $att | awk '{print $1}')
    origsize=$(echo $att | awk '{print $4}')
    newsize=$(( $origsize + $incr ))
    aws ec2 modify-volume --volume-id $volume --size $newsize
    sleep 60
    function growfs {
      case $fs in
          ext[2-4])
             resize2fs $partition
          ;;
          xfs)
             xfs_growfs $partition                                                   ;;
      esac
    }
    if [ $ispart -eq "loop" ]
    then
        echo "Resizing Raw disk"
        growfs
    else
        echo "Resizing Partition"
        growpart $partition
        growfs
    fi
    echo "The $partition has been resized. You now are using $usep%."
  fi
done