Attaching a new volume each time a node group is scaled

Can anyone share any reference template to create a new volume and attach to a new instance each time a deployment for that instance is scaled up?

My template looks like:

node_templates:
  key_pair:
    ...
  vol:
    ...
  node_host:
    ...
    relationships:
      ...
      - key_pair
      - vol
  node:
    ...
    relationships:
      - type: cloudify.relationships.contained_in
        target: node_host
      ...

groups:
  scale_up_group:
    members: [node, node_host, vol]
    policies:
      auto_scale_up:
        type: scale_policy_type
        properties:
          policy_operates_on_group: true
          scale_limit: 6
          scale_direction: '<'
          scale_threshold: 15
          service_selector: cpu.total.user
          cooldown_time: 60
        triggers:
          execute_scale_workflow:
            type: cloudify.policies.triggers.execute_workflow
            parameters:
              workflow: scale
              workflow_parameters:
                delta: 1
                scalable_entity_name: node
                scale_compute: true

Courtesy of Trammell from cloudify-user group:

node_templates:
  key_pair:
    type: cloudify.openstack.nodes.KeyPair
    ...

  floating_ip:
    type: cloudify.openstack.nodes.FloatingIP
    ...

  vol:
    type: cloudify.openstack.nodes.Volume
    ...
  node_host:
    type: cloudify.openstack.nodes.Server
    ...

    relationships:
      - type: cloudify.openstack.server_connected_to_keypair
        target: keypair
      - type: cloudify.openstack.server_connected_to_floating_ip
        target: floating_ip
      - type: cloudify.relationships.depends_on
        target: vol

  node:
    type: custom.node.type
    ...
    relationships:
      - type: cloudify.relationships.contained_in
        target: node_host
      ...

groups:
  scale_vm:
    members: [node, node_host, floating_ip, vol]



  scale_up_group:
    members: [node, node_host, floating_ip, vol]
    policies:
      auto_scale_up:
        type: scale_policy_type
        properties:
          policy_operates_on_group: true
          scale_limit: 6
          scale_direction: '<'
          scale_threshold: 15
          service_selector: cpu.total.user
          cooldown_time: 60
        triggers:
          execute_scale_workflow:
            type: cloudify.policies.triggers.execute_workflow
            parameters:
              workflow: scale
              workflow_parameters:
                delta: 1
                scalable_entity_name: scale_vm
                scale_compute: true

policies:
  scale_vm_policy:
    type: cloudify.policies.scaling
    properties:
      default_instances:  1
    targets: [scale_vm]

Ref: https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!topic/cloudify-users/TPepGofpSBU