/sys/class/net/tapdbfe88f8-06/carrier: open failed: No such file or directory

It seems you have no eth0 into the bridge br-eth0:
 Bridge "br-eth0"
        Port "br-eth0"
            Interface "br-eth0"
                type: internal
        Port "phy-br-eth0"
            Interface "phy-br-eth0
So add eth0 into br-eth0 so that two nodes can link together.
sudo ovs-vsctl add-port br-eth0 eth0

U can move all the ips on eth0 to br-eth0 and bring br-eth0 up:
sudo ip addr add xxx-on-eth0 dev br-eth0
sudo ip addr flush eth0 (correct me if I am wrong with this command)
sudo ifconfig br-eth0 up

to gongysh
great! thx a lot gong~

the problem is fixed.
command should be like:

sudo ovs-vsctl add-port br-eth0 eth0
sudo ip addr add x.x.x.x/24 dev br-eth0 (x.x.x.x/24 is my eth0 ip which should be moved to br-eth0)
sudo ip addr flush eth0
sudo ifconfig br-eth0 up

I think I have a similar problem.
Instances from my node 1 that is the control & compute get IP address and can receive metadata, but instances from node 2 which is only compute do not get any ip addres from dhcp.
My current setup is :

NODE1:
Interfaces:
# VM internet Access
auto eth1
iface eth1 inet manual
up ifconfig $IFACE 0.0.0.0 up
up ip link set $IFACE promisc on
down ip link set $IFACE promisc off
down ifconfig $IFACE down

#For Exposing OpenStack API over the internet
auto br-ex
iface br-ex inet static
address 192.168.100.6
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 8.8.8.8

#Not internet connected(used for OpenStack management)
auto eth0
iface eth0 inet static
address 10.10.100.51
netmask 255.255.255.0

root@openstackmanagement:~# ovs-vsctl show
68b8533e-a28b-4ded-8591-5b2919803c45
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "qg-605e3b38-5a"
            Interface "qg-605e3b38-5a"
                type: internal
        Port "eth1"
            Interface "eth1"
    Bridge br-int
        Port "tap1b0d38a4-01"
            tag: 1
            Interface "tap1b0d38a4-01"
                type: internal
        Port "qvoce730253-05"
            tag: 1
            Interface "qvoce730253-05"
        Port "qr-c5318f6a-8b"
            tag: 1
            Interface "qr-c5318f6a-8b"
                type: internal
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
        Port br-int
            Interface br-int
                type: internal
    Bridge br-tun
        Port br-tun
            Interface br-tun
                type: internal
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
    ovs_version: "1.4.0+build0"

root@openstackmanagement:~# ovs-dpctl show
system@br-tun:
        lookups: hit:17 missed:136 lost:0
        flows: 0
        port 0: br-tun (internal)
        port 1: patch-int (patch: peer=patch-tun)
system@br-int:
        lookups: hit:132 missed:576 lost:0
        flows: 0
        port 0: br-int (internal)
Aug 01 12:01:18|00001|netdev_linux|WARN|/sys/class/net/tap1b0d38a4-01/carrier: open failed: No such file or directory
        port 1: tap1b0d38a4-01 (internal)
        port 7: patch-tun (patch: peer=patch-int)
Aug 01 12:01:18|00002|netdev_linux|WARN|/sys/class/net/qr-c5318f6a-8b/carrier: open failed: No such file or directory
        port 8: qr-c5318f6a-8b (internal)
        port 9: qvoce730253-05
system@br-ex:
        lookups: hit:177391 missed:88398 lost:0
        flows: 19
        port 0: br-ex (internal)
        port 1: eth1
Aug 01 12:01:18|00003|netdev_linux|WARN|/sys/class/net/qg-605e3b38-5a/carrier: open failed: No such file or directory
        port 3: qg-605e3b38-5a (internal)

NODE 2:
Interfaces:
auto eth1
iface eth1 inet manual
up ifconfig $IFACE 0.0.0.0 up
up ip link set $IFACE promisc on
down ip link set $IFACE promisc off
down ifconfig $IFACE down

#For Exposing OpenStack API over the internet
auto br-ex
iface br-ex inet static
address 192.168.100.7
netmask 255.255.255.0
gateway 192.168.100.1
dns-nameservers 8.8.8.8

#Not internet connected(used for OpenStack management)
auto eth0
iface eth0 inet static
address 10.10.100.52
netmask 255.255.255.0

root@openstack2:~# ovs-vsctl show
12fbf5c5-072f-47ba-9489-689c02e1c8e0
    Bridge br-tun
        Port br-tun
            Interface br-tun
                type: internal
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
    Bridge br-int
        Port br-int
            Interface br-int
                type: internal
        Port "qvo7a73a532-c1"
            Interface "qvo7a73a532-c1"
        Port "qvob4ae521c-33"
            Interface "qvob4ae521c-33"
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "eth1"
            Interface "eth1"
    ovs_version: "1.4.0+build0"

root@openstack2:~# ovs-dpctl show
system@br-tun:
        lookups: hit:0 missed:0 lost:0
        flows: 0
        port 0: br-tun (internal)
system@br-int:
        lookups: hit:6210 missed:1390 lost:0
        flows: 27
        port 0: br-int (internal)
        port 1: eth0
        port 3: qvob4ae521c-33
system@br-ex:
        lookups: hit:2775 missed:1223 lost:0
        flows: 17
        port 0: br-ex (internal)
        port 1: eth1

Can anyone help me ?

ERROR [quantum.plugins.openvswitch.agent.ovs_quantum_agent] Failed to create OVS patch port. Cannot have tunneling enabled on this agent, since this version of OVS does not support tunnels or patch ports. Agent terminated!

I solved the problem. It was a problem with openvswitch-agent from NODE 2 (compute node)
I had to :

apt-get remove openvswitch-switch openvswitch-datapath-dkms quantum-plugin-openvswitch-agent
reboot
apt-get install openvswitch-switch openvswitch-datapath-dkms quantum-plugin-openvswitch-agent
reboot

And after that it worked.