HA : contrail-api throws an exception during rabbit reconnection and fails to connect back

HA : contrail-api throws an exception during rabbit reconnection and fails to connect back during node failures.

Issue observed on R2.20 build 57 .

ERROR:a12c4s2:contrail-api:Config:0:__default__ [SYS_ERR]: VncApiError: RabbitMQ connection down
WARNING:a12c4s2:contrail-api:Config:0:__default__ [SYS_NOTICE]: VncApiError: RabbitMQ connection ESTABLISHED <Connection: amqp://guest@5.5.5.100:5673// at 0x7f52c6c2a650>
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/gevent/greenlet.py", line 327, in run
    result = self._run(*self.args, **self.kwargs)
  File "/usr/lib/python2.7/dist-packages/cfgm_common/vnc_kombu.py", line 112, in _connection_watch
    self._reconnect()
  File "/usr/lib/python2.7/dist-packages/cfgm_common/vnc_kombu.py", line 99, in _reconnect
    callbacks=[self._subscribe])
  File "/usr/lib/python2.7/dist-packages/kombu/messaging.py", line 357, in __init__
    self.revive(self.channel)
  File "/usr/lib/python2.7/dist-packages/kombu/messaging.py", line 369, in revive
    self.declare()
  File "/usr/lib/python2.7/dist-packages/kombu/messaging.py", line 379, in declare
    queue.declare()
  File "/usr/lib/python2.7/dist-packages/kombu/entity.py", line 505, in declare
    self.queue_declare(nowait, passive=False)
  File "/usr/lib/python2.7/dist-packages/kombu/entity.py", line 531, in queue_declare
    nowait=nowait)
  File "/usr/lib/python2.7/dist-packages/amqp/channel.py", line 1258, in queue_declare
    (50, 11), # Channel.queue_declare_ok
  File "/usr/lib/python2.7/dist-packages/amqp/abstract_channel.py", line 67, in wait
    self.channel_id, allowed_methods)
  File "/usr/lib/python2.7/dist-packages/amqp/connection.py", line 237, in _wait_method
    self.method_reader.read_method()
  File "/usr/lib/python2.7/dist-packages/amqp/method_framing.py", line 189, in read_method
    raise m
IOError: Socket closed
<Greenlet at 0x7f52c6c179b0: <bound method VncServerKombuClient._connection_watch of <vnc_cfg_api_server.vnc_cfg_ifmap.VncServerKombuClient object at 0x7f52c7dcb5d0>>> failed with IOError

Due to this issue it was not able to create a routing instance reference to virtual-network.

root@a12c3s4:~# curl -uadmin:contrail123 http://127.0.0.1:8095/virtual-network/0eb1b97d-ebfb-45ae-9df9-5c81b3ab485a | python -mjson.tool
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
100 1522 100 1522 0 0 217k 0 --:--:-- --:--:-- --:--:-- 247k
{
    "virtual-network": {
        "display_name": "vn1000",
        "fq_name": [
            "default-domain",
            "TestHANode-15391225",
            "vn1000"
        ],
        "href": "http://127.0.0.1:8095/virtual-network/0eb1b97d-ebfb-45ae-9df9-5c81b3ab485a",
        "id_perms": {
            "created": "2015-06-20T02:39:52.574968",
            "creator": null,
            "description": null,
            "enable": true,
            "last_modified": "2015-06-20T02:39:53.170435",
            "permissions": {
                "group": "admin",
                "group_access": 7,
                "other_access": 7,
                "owner": "admin",
                "owner_access": 7
            },
            "user_visible": true,
            "uuid": {
                "uuid_lslong": 11383231245290522714,
                "uuid_mslong": 1058831337889940910
            }
        },
        "is_shared": false,
        "name": "vn1000",
        "network_ipam_refs": [
            {
                "attr": {
                    "host_routes": null,
                    "ipam_subnets": [

                        {
                            "addr_from_start": true,
                            "allocation_pools": [],
                            "default_gateway": "20.1.1.1",
                            "dhcp_option_list": null,
                            "dns_nameservers": [],
                            "dns_server_address": "20.1.1.2",
                            "enable_dhcp": true,
                            "host_routes": null,
                            "subnet": {
                                "ip_prefix": "20.1.1.0",
                                "ip_prefix_len": 24
                            },
                            "subnet_name": "",
                            "subnet_uuid": "df014aec-8215-4a9b-8c52-2b584aea6227"
                        }
                    ]
                },
                "href": "http://127.0.0.1:8095/network-ipam/947f9a4d-c0e9-4856-9df5-4834ebe1df3b",
                "to": [
                    "default-domain",
                    "default-project",
                    "default-network-ipam"
                ],
                "uuid": "947f9a4d-c0e9-4856-9df5-4834ebe1df3b"
            }
        ],
        "parent_href": "http://127.0.0.1:8095/project/ebb3c3a2-e9bf-456c-8686-a175c86b6a1c",
        "parent_type": "project",
        "parent_uuid": "ebb3c3a2-e9bf-456c-8686-a175c86b6a1c",
        "route_target_list": {
            "route_target": [
                "target:64512:12345"
            ]
        },
        "router_external": false,
        "uuid": "0eb1b97d-ebfb-45ae-9df9-5c81b3ab485a"
    }
}
root@a12c3s4:~#