ceph_wipe_disk.yaml

# Instructions:
# 1. save this file somewhere, for example /home/stack/ceph_wipe_disk.yaml
# 2. create an empty ceph_wipe_env.yaml with the following contents:
#
# resource_registry:
#   OS::TripleO::NodeUserData: /home/stack/ceph_wipe_disk.yaml
# parameter_defaults:
#   ceph_disks: "/dev/sdb /dev/sdc"
#
# 3. when deploying, add to the CLI command the following argument:
#
# -e /path/to/ceph_wipe_env.yaml

heat_template_version: 2014-10-16

parameters:
  ceph_disks:
    type: string
    description: A list of block devices to be cleared with an empty GPT label.
    default: "/dev/sdb /dev/sdc"

description: >
  This is an example showing how you can clear the cephstorage nodes disk with an empty GPT label on firstboot.

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

  wipe_disk:
    type: OS::Heat::SoftwareConfig
    properties:
      config:
        str_replace: 
          template: |
            #!/bin/bash
            case "$(hostname)" in
              *cephstorage*)
                for d in $disks; do
                  if [ -b ${d} ]; then
                    echo "Wiping disk ${d} ..."
                    sgdisk -Z ${d}
                    sgdisk -o ${d}
                  fi
                done
              ;;
            esac
          params:
            $disks: {get_param: ceph_disks}

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

hi, I think best option to make sure this is applied only on the relevant nodes is to add role-specific NodeUserData in the parent templates, what do you think?