stack-delete fails when deleting a template with resource group

[jz]

using the below template created a stack. but delete will fail

heat_template_version: 2015-04-30

description: Simple template to deploy 100 compute instances

parameters:
  image_name:
    type: string
  instance_count:
    type: number
    default: 2

resources:
   net:
      type: OS::Neutron::Net
      properties:
         admin_state_up: true
  subnet:
      type: OS::Neutron::Subnet
      properties:
         cidr: 10.0.0.0/24
         enable_dhcp: true
         network_id: { get_resource: net }
         allocation_pools:
         - start: 10.0.0.1
           end: 10.0.0.10

  instances:
    type: OS::Heat::ResourceGroup
    properties:
      count: { get_param: instance_count }
      resource_def:
        type: OS::Nova::Server
        properties:
          image: { get_param: image_name }
          flavor: { get_param: flavor_name }
          networks:
             - network: { get_resource: net }

when deleting the stack, it seemed that heat did not calclulate the dependencies correctly, and tried
to delete the subnet first which led to a conflict:
"Conflict: Unable to complete operation on subnet bb7a7d76-e651-4f9e-a205-3756999de58a. One or more ports have an IP allocation from this subnet"

[Rabi Mishra (rabi)]

I think you can get around this issue by adding explicit dependency 'depends-on' to 'instances' or use the subnet with the server networks property.

ex.

instances:
    type: OS::Heat::ResourceGroup
    depends_on: subnet

or

          networks:
             - subnet: { get_resource: subnet }

There is check for the OS::Nova::Server to check for subnets[1] in the same stack. However, it does not work with ResourceGroup as it's nested stack and the subnet is in the parent/root stack.

However, the template you used results in a non deletable stack which is worrying.

[1] https://github.com/openstack/heat/blob/master/heat/engine/resources/openstack/nova/server.py#L987-L998

[jz (danielradcliffe2004)]

I know add depends_on is a work around and has tried that already. But I think even
without depends_on, heat should handle the dependency correctly in this case.

[tom king (kingttx)]

This also affects VIO 3.1.

[Rabi Mishra (rabi)]

We probably don't have a way to handle this atm. You can surely use the workaround in comment #1.