snapshot image of server left after the stack deleted

[huangtianhua]

1. create a stack with the snippet:
*********************
resources:
  server_1:
    type: OS::Nova::Server
    properties:
      name: ser1
      flavor: {get_param: flavor}
      image: {get_param: image}
      networks:
        - port: {get_resource: port_1}
      tags:
        - t1
  server_2:
    type: OS::Nova::Server
    properties:
      name: ser2
      flavor: {get_param: flavor}
      image: {get_param: image}
      networks:
        - port: {get_resource: port_2}
  port_1:
    type: OS::Neutron::Port
    properties:
      network: private
    port_2:
    type: OS::Neutron::Port
    properties:
      network: private
************************
2. snapshot for the stack
3. update the stack to remove the 'server_2' resource
4. delete the stack

The stack and resources deleted successfully, but the image for the resource 'server_2' left.

[Thomas Herve (therve)]

Can you explain a bit more? Why would the image of the server be deleted?

[huangtianhua (huangtianhua)]

For step 2 we create the snapshot for the stack, create images for the two servers ('external_ser' and 'th_server'), when we delete the stack, the snapshot image of 'th_server' be deleted as expected,see the code:
https://github.com/openstack/heat/blob/master/heat/engine/stack.py#L1926-L1940

for name, rsrc in six.iteritems(self.resources):
            snapshot_data = snapshot.data
            if snapshot_data:
                data = snapshot.data['resources'].get(name)
                scheduler.TaskRunner(rsrc.delete_snapshot, data)()

We iterate the resources of the stack which has removed the resource 'external_ser' when update, so the snapshot image of the resource 'external_ser' left.
Maybe we should make sure the snapshot image be deleted when remove the resource 'external_ser'.

[Rabi Mishra (rabi)]

IMO we should not even snapshot an external resource when doing a stack snapshot, as it's not managed by heat.

[huangtianhua (huangtianhua)]

@Rabi Mishra,
In fact this bug is not related with the 'external' resource, just my template with it. If you remove a normal server resource, the bug is still happen. Of course, I think you mentioned another bug: don't snapshot an external resource when doing a stack :)

[huangtianhua (huangtianhua)]

I register a bug https://bugs.launchpad.net/heat/+bug/1717178

[huangtianhua (huangtianhua)]

I have modified the bug description to use the normal resources.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/504862