I am setting up an OpenStack Havana deployment using 1 controller node, 1 compute node and 1 network node, with Neutron. I have chosen to use GRE tunneling as the networking technology.

However, the GRE tunnels necessary for virtual networking between the compute and network nodes are not being created due to the following error (which can be see in both network and compute hosts' /var/log/neutron/openvswitch-agent.log):

2013-11-03 01:20:00.358 1473 ERROR neutron.agent.linux.ovs_lib [-] Unable to execute ['ovs-ofctl', 'add-flow', 'br-tun', 'hard_timeout=0,idle_timeout=0,priority=1,in_port=-1,actions=resubmit(,2)']. Exception:
Command: ['sudo', '/usr/bin/neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ovs-ofctl', 'add-flow', 'br-tun', 'hard_timeout=0,idle_timeout=0,priority=1,in_port=-1,actions=resubmit(,2)']
Exit code: 1
Stdout: ''
Stderr: 'ovs-ofctl: -1: negative values not supported for in_port\n'

Here are some interesting outputs:

sudo ovs-vsctl show

(...)
Bridge br-tun
        Port "gre-2"
            Interface "gre-2"
                type: gre
                options: {in_key=flow, local_ip="192.168.10.31", out_key=flow, remote_ip="192.168.10.32"}
(...)

sudo ovs-ofctl show br-tun

OFPT_FEATURES_REPLY (xid=0x2): dpid:00002a8895eae34a
n_tables:254, n_buffers:256
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: OUTPUT SET_VLAN_VID SET_VLAN_PCP STRIP_VLAN SET_DL_SRC SET_DL_DST SET_NW_SRC SET_NW_DST SET_NW_TOS SET_TP_SRC SET_TP_DST ENQUEUE
 1(patch-int): addr:ea:68:bf:31:b8:f1
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 LOCAL(br-tun): addr:2a:88:95:ea:e3:4a
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0

So, port gre-2 is missing in the OpenFlow switch.

I have confirmed my configurations over and over again and still haven't found the culprit. It was almost entirely based in the official guide for Havana on Ubuntu 12.04 LTS.

What should I check first?

I'd be very grateful if someone could help me.

Thank you.