heat stack-update removes existing ip configuration

Issue

• heat stack-update removes existing ip configuration

• If the number of instances is increased in the heat stack, the old VMs are losing their network configuration

• The following templates are being used

group.yaml

heat_template_version: 2014-10-16
resources:

  server:
    type: OS::Heat::ResourceGroup
    properties:
      count: 3
      resource_def: {type: fedora.yaml}

fedora.yaml

heat_template_version: 2014-10-16
resources:

  init:
     type: OS::Heat::CloudConfig
     properties:
       cloud_config:
         chpasswd:
          list: |
            root:XXX
            fedora:XXX
          expire: False
         ssh_pwauth: True

  port:
    type: OS::Neutron::Port
    properties:
      network_id: 0eaf58df-6512-4ba7-9865-e92ba7b747a2
      replacement_policy: REPLACE_ALWAYS

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: dce58c34-9d3f-4b1d-ad70-d3de7a762b7a
      port_id: { get_resource: port }

  server:
    type: OS::Nova::Server
    properties:
      flavor: m1.small
      image: fedora22_cloud
      networks:
        - port: { get_resource: port }
      user_data_format: RAW
      user_data:
        get_resource: init

• There're no issues creating a stack with heat stack-create group -f group.yaml

+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                            |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+
| c47c0298-0fec-4d52-a649-b5754ed7f704 | gr-er-3vzlom4ezpvd-0-jmmzqdvo4mc2-server-x67c3d3kse7i | ACTIVE | -          | Running     | internal=192.168.1.52, 172.29.15.40 |
| 1ad8790f-109f-4de4-a430-a54cd719e63f | gr-er-3vzlom4ezpvd-1-ublf5mhxouu7-server-ejrdxadabnnp | ACTIVE | -          | Running     | internal=192.168.1.53, 172.29.15.41 |
| fcbc2d71-da78-4181-83d2-b73405fc76bd | gr-er-3vzlom4ezpvd-2-m4acj4ber2ll-server-kb6ixvg4lqpp | ACTIVE | -          | Running     | internal=192.168.1.54, 172.29.15.42 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+

• When the count property within the group.yaml file is increased to 4 and the stack is updated with heat stack-update group -f group.yaml, all previously existing VMs are losing their network configuration and only the new one have a network configuration

+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                            |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+
| c47c0298-0fec-4d52-a649-b5754ed7f704 | gr-er-3vzlom4ezpvd-0-jmmzqdvo4mc2-server-x67c3d3kse7i | ACTIVE | -          | Running     |                                     |
| 1ad8790f-109f-4de4-a430-a54cd719e63f | gr-er-3vzlom4ezpvd-1-ublf5mhxouu7-server-ejrdxadabnnp | ACTIVE | -          | Running     |                                     |
| fcbc2d71-da78-4181-83d2-b73405fc76bd | gr-er-3vzlom4ezpvd-2-m4acj4ber2ll-server-kb6ixvg4lqpp | ACTIVE | -          | Running     |                                     |
| 2e9eef04-4317-4de4-ada2-66161ddeb44c | gr-er-3vzlom4ezpvd-3-n3yewelbodfi-server-2dya5a4czv5z | ACTIVE | -          | Running     | internal=192.168.1.55, 172.29.15.43 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+-------------------------------------+