Hi folks, I have a couple of very basic questions here due to a lack of understanding around some core concepts I'm afraid.

I have a dual node setup consisting of a combined controller / network host and separate compute host each with a single NIC. Unfortunately I'm having trouble accessing running instances. Some background:

• The network I'm on has no spare IP addresses so I cannot set up an external network with floating ip's.
• I have an internal network set up (with an internal router), but cannot seem to access it from the compute / controller nodes. (should I be able to without the external net?)
• 'nova list' shows an instance with an ip, but the instance itself can't see the network. (its a simple ubuntu cloudimg)
• nova ssh instance reports: ERROR: No public addresses found for 'test2'. (test2 being the name of the instance)

One thing I'm particularly confused about is how a single nic setup should work. I have added two bridges, br-ex and br-int. I have moved the external ip from eth0 to br-ex, (as per http://openstack.redhat.com/forum/discussion/628/havana-neutron-does-br-ext-and-br-int-have-ips/p1 (http://openstack.redhat.com/forum/dis...) ) but I've done nothing with br-int. (I've done this on both the network and compute hosts) So I guess my questions are as follows:

• Should I need an external network / router to access the vm's from the compute host?
• Am I missing a few steps in order to make this work with a single NIC?

Any help / context / pointers would be much appreciated.

COMPUTE:
-bash-4.1$ sudo ovs-vsctl show
b546a82c-648a-4d07-b26b-1519e7f809ca
    Bridge br-tun
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
        Port "gre-2"
            Interface "gre-2"
                type: gre
                options: {in_key=flow, local_ip="10.163.136.68", out_key=flow, remote_ip="10.163.131.123"}
        Port br-tun
            Interface br-tun
                type: internal
    Bridge br-ex
        Port "eth0"
            Interface "eth0"
        Port br-ex
            Interface br-ex
                type: internal
    Bridge br-int
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
        Port br-int
            Interface br-int
                type: internal
        Port "qvo6663ea21-f2"
            Interface "qvo6663ea21-f2"

CONTROLLER:
-bash-4.1$ sudo ovs-vsctl show
f1080aa4-2508-464a-ac17-03b4f211dce3
    Bridge br-int
        Port "tapdbaded17-55"
            tag: 1
            Interface "tapdbaded17-55"
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
        Port "tap56c37fd2-d0"
            tag: 1
            Interface "tap56c37fd2-d0"
        Port br-int
            Interface br-int
                type: internal
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "eth0"
            Interface "eth0"
    Bridge br-tun
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
        Port br-tun
            Interface br-tun
                type: internal
        Port "gre-1"
            Interface "gre-1"
                type: gre
                options: {in_key=flow, local_ip="10.163.131.123", out_key=flow, remote_ip="10.163.136.68"}

-bash-4.1$ neutron router-show 2f44dfb8-f0ab-4b4d-9a74-13aa81940a95
+-----------------------+--------------------------------------+
| Field                 | Value                                |
+-----------------------+--------------------------------------+
| admin_state_up        | True                                 |
| external_gateway_info |                                      |
| id                    | 2f44dfb8-f0ab-4b4d-9a74-13aa81940a95 |
| name                  | admin-internal-router                |
| routes                |                                      |
| status                | ACTIVE                               |
| tenant_id             | 3280618841f44ca0924977ab42ffde8b     |
+-----------------------+--------------------------------------+
-bash-4.1$ neutron net-show 798285f7-75aa-44cc-a86b-5aceaab5276f
+---------------------------+--------------------------------------+
| Field                     | Value                                |
+---------------------------+--------------------------------------+
| admin_state_up            | True                                 |
| id                        | 798285f7-75aa-44cc-a86b-5aceaab5276f |
| name                      | admin-internal-net                   |
| provider:network_type     | gre                                  |
| provider:physical_network |                                      |
| provider:segmentation_id  | 3                                    |
| router:external           | False                                |
| shared                    | False                                |
| status                    | ACTIVE                               |
| subnets                   | e6b11e6a-9a03-4b02-a8e9-e07bfcc2aa8f |
| tenant_id                 | 3280618841f44ca0924977ab42ffde8b     |
+---------------------------+--------------------------------------+
-bash-4.1$ neutron subnet-show e6b11e6a-9a03-4b02-a8e9-e07bfcc2aa8f
+------------------+--------------------------------------------------+
| Field            | Value                                            |
+------------------+--------------------------------------------------+
| allocation_pools | {"start": "192.168.1.2", "end": "192.168.1.254"} |
| cidr             | 192 ...