gistfile1.txt

heat_template_version: 2014-10-16

description: >
  Wipe and convert all disks to GPT (except the disk containing the root file system)

resources:
  userdata:
    type: OS::Heat::MultipartMime
    properties:
      parts:
      - config: {get_resource: wipe_disk}

  wipe_disk:
    type: OS::Heat::SoftwareConfig
    properties:
      config: {get_file: wipe-disk.sh}

outputs:
  OS::stack_id:
    value: {get_resource: userdata}

wipe-disk.sh

#!/bin/bash
NRDISKS=$(lsblk -no NAME,TYPE,MOUNTPOINT | grep "disk" | awk '{print $1}' | wc -l)
/bin/logger -t DISKWIPE "Number of disks detected: $NRDISKS"
for DEVICE in $(lsblk -no NAME,TYPE,MOUNTPOINT | grep "disk" | awk '{print $1}')
do
  ROOTFOUND=0
  /bin/logger -t DISKWIPE "Checking /dev/$DEVICE..."
  NRPARTITIONS=$(expr $(lsblk -n /dev/$DEVICE | awk '{print $7}' | wc -l) - 1)
  /bin/logger -t DISKWIPE "Number of partitions on /dev/${DEVICE}: $NRPARTITIONS"
  for MOUNTS in $(lsblk -n /dev/$DEVICE | awk '{print $7}')
  do
    if [ "$MOUNTS" = "/" ]
    then
      ROOTFOUND=1
    fi
  done
  if [ $ROOTFOUND = 0 ]
  then
    /bin/logger -t DISKWIPE "Root not found in /dev/${DEVICE}"
    /bin/logger -t DISKWIPE "Wiping disk /dev/${DEVICE}"
    sgdisk -Z /dev/${DEVICE}
    sgdisk -g /dev/${DEVICE}
  else
    /bin/logger -t DISKWIPE "Root found in /dev/${DEVICE}"
  fi
done