Wrong 'fixed_ips' defaults in OS::Neutron::Port

[Alexander Ignatov]

Let's assume we have an template:
{
    "Resources" : {
        "port" : {
            "Type" : "OS::Neutron::Port",
            "Properties" : {
               "network_id" : "daeb24b2-5edd-43f4-abdf-11355c78a27f"
            }
        }
    }
}

In this case after stack-create Neutron will create port without assigned fixed_ips. This this because heat engine explicitly assigns default value for 'fixed_ips'=[]. See here:
https://github.com/openstack/heat/blob/master/heat/engine/resources/neutron/port.py#L75

It is wrong behaviour because in case of missing 'fixed_ips' neutron should assign some fixed ip address to the port. Look how it is implemented in neutronclient:
==================example.py==============
from neutronclient.v2_0 import client as neutron_client

neutron = neutron_client.Client(
    username="admin",
    password="nova",
    tenant_name="admin",
    auth_url="http://172.18.79.141:5000/v2.0/")

# Case 1. Creating port with missed fixed_ips param
neutron.create_port({'port': {'network_id': '4735f69e-c9e7-444c-a8bb-b8ec361a4f72',
                                     'name': 'port_with_ip',
                                     'security_groups': [],
                                     'admin_state_up': True} })

# Case 2. Creating port with fixed_ips=[]
neutron.create_port({'port': {'network_id': '4735f69e-c9e7-444c-a8bb-b8ec361a4f72',
                                     'name': 'port_without_ip',
                                     'security_groups': [],
                                     'fixed_ips': [],
                                     'admin_state_up': True} })
========================================

In the above example created ports will look like are as follows:
stack@stack:~$ neutron port-list
| some-uuid1 | port_with_ip | fa:16:3e:53:f3:4b | {"subnet_id": "495328abcf60", "ip_address": "10.0.0.14"} |
| some-uuid2 | port_without_ip | fa:16:3e:55:6f:2d | |

============================================

If you can see in case 1 when 'fixed_ips' param is missed in port definintion neutron automatically assigns some address and subnet.

So Heat should allow both cases with missed fixed_ips and user-defined.

[Thomas Herve (therve)]

Okay, that's unfortunate, but who thought that doing that in Neutron was a good idea? I mean seriously this is a really strange behavior, and completely implicit. I'm okay to fix that in Heat, but I think a bug should be reported in Neutron to fix this.

[Eugene Nikanorov (enikanorov)]

Thomas, why do you think it is a strange behavior? You get exactly what you ask for: a port with fixed_ips = []

[Thomas Herve (therve)]

Eugene: I'm not saying that the behavior with fixed_ips = [] is strange, but that omitting fixed_ips and passing an empty list giving you different behavior is counter-intuitive.

Nowhere in the documentation I can find mention of that.

On top of that, we already had to fix bugs like bug #1224472 so that means for the same attribute None is not valid, empty list and omitting the attribute gives you different behavior. That is super confusing, at least to me.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/68648

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/68648
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=0cfdd6e280616de4c9fd5b6a1819e39b6e7fd775
Submitter: Jenkins
Branch: master

commit 0cfdd6e280616de4c9fd5b6a1819e39b6e7fd775
Author: Sergey Kraynev <email address hidden>
Date: Thu Jan 23 09:37:28 2014 -0500

    Delete fixed_ips if it's empty list

    If neutronclient gets fixed_ips = [], created port will not get assigned
    ip address. In current patch fixed_ips will be deleted from properties,
    if it is empty list. So created port always gets assigned ip address.

    Change-Id: I8344180b07ffb61019264f44d23aa400aa1ace31
    Closes-bug: #1271597