Description of problem:
After deploying a telco OVN-DPDK + SR-IOV deployment with DVR disabled, it appears that the guest instances are unable to download metadata fron nova metadata API service.

All networking-ovn-metadata-agent agents are running:
+--------------------------------------+------------------------------+-----------------------------------+-------------------+-------+-------+-------------------------------+
| ID                                   | Agent Type                   | Host                              | Availability Zone | Alive | State | Binary                        |
+--------------------------------------+------------------------------+-----------------------------------+-------------------+-------+-------+-------------------------------+
| 71723433-d4a9-4ee9-9d9c-3e846544e603 | NIC Switch agent             | computeovndpdksriov-1.localdomain | None              | :-)   | UP    | neutron-sriov-nic-agent       |
| e9f36491-bca9-4c3e-8be6-74793777fa29 | NIC Switch agent             | computeovndpdksriov-0.localdomain | None              | :-)   | UP    | neutron-sriov-nic-agent       |
| a15f7f3e-f8c2-408a-a9dd-68570f9797e4 | OVN Controller agent         | computeovndpdksriov-1.localdomain |                   | :-)   | UP    | ovn-controller                |
| 9e1a5e19-00fb-4229-b002-7832f90ababf | OVN Metadata agent           | computeovndpdksriov-1.localdomain |                   | :-)   | UP    | networking-ovn-metadata-agent |
| 6e4b94b6-70ce-44cf-ac0c-0869f9e146ac | OVN Controller agent         | computeovndpdksriov-0.localdomain |                   | :-)   | UP    | ovn-controller                |
| f252611c-f8c0-424e-adbc-916a7afd4fad | OVN Metadata agent           | computeovndpdksriov-0.localdomain |                   | :-)   | UP    | networking-ovn-metadata-agent |
| f4d136e4-cc7d-4941-9e6d-661c59808a81 | OVN Controller Gateway agent | controller-1.localdomain          |                   | :-)   | UP    | ovn-controller                |
| e6a989da-ed22-4246-949c-138252f33db7 | OVN Metadata agent           | controller-1.localdomain          |                   | :-)   | UP    | networking-ovn-metadata-agent |
| 54a453c8-0674-4b72-978a-eb9740d1a9c7 | OVN Controller Gateway agent | controller-0.localdomain          |                   | :-)   | UP    | ovn-controller                |
| 59417f27-d944-4220-8248-6b40862660d5 | OVN Metadata agent           | controller-0.localdomain          |                   | :-)   | UP    | networking-ovn-metadata-agent |
| d8eec782-46db-40ca-9646-ac3876543254 | OVN Controller Gateway agent | controller-2.localdomain          |                   | :-)   | UP    | ovn-controller                |
| 2d5695fd-7ed6-4041-80e2-c68ec4916e54 | OVN Metadata agent           | controller-2.localdomain          |                   | :-)   | UP    | networking-ovn-metadata-agent |
+--------------------------------------+------------------------------+-----------------------------------+-------------------+-------+-------+-------------------------------+

Inside the guest, the routing appears to be correct:
[root@localhost ~]# ip r
default via 20.10.114.254 dev eth0 proto dhcp metric 100
20.10.114.0/24 dev eth0 proto kernel scope link src 20.10.114.199 metric 100
169.254.169.254 via 20.10.114.100 dev eth0 proto dhcp metric 100

And there is network connectivity to the metadata API service:
[root@localhost ~]# ping -c 1 169.254.169.254
PING 169.254.169.254 (169.254.169.254) 56(84) bytes of data.
64 bytes from 169.254.169.254: icmp_seq=1 ttl=64 time=0.845 ms

--- 169.254.169.254 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.845/0.845/0.845/0.000 ms

But we're unable to download data from the service:
[root@localhost ~]# curl http://169.254.169.254
curl: (7) Failed connect to 169.254.169.254:80; Connection timed out

On the hypervisor we can see the created namespace:
[root@computeovndpdksriov-1 ~]# ip netns
ovnmeta-5737c80f-2b2f-4614-b6b2-94b494001256 (id: 0)

We can view the tap interface:
[root@computeovndpdksriov-1 ~]# ip netns exec ovnmeta-5737c80f-2b2f-4614-b6b2-94b494001256 ip r
20.10.114.0/24 dev tap5737c80f-21 proto kernel scope link src 20.10.114.100
169.254.0.0/16 dev tap5737c80f-21 proto kernel scope link src 169.254.169.254

The required tap interface is attached to br-int (dev tap5737c80f-20):
[root@computeovndpdksriov-1 ~]# ovs-vsctl show | less
    Bridge br-int
        fail_mode: secure
        datapath_type: netdev
        Port br-int
            Interface br-int
                type: internal
        Port tap5737c80f-20
            Interface tap5737c80f-20
        Port vhu17bd1131-4a
            Interface vhu17bd1131-4a
                type: dpdkvhostuserclient
                options: {vhost-server-path="/var/lib/vhost_sockets/vhu17bd1131-4a"}
        Port ovn-54a453-0
            Interface ovn-54a453-0
                type: geneve
                options: {csum="true", key=flow, remote_ip="10.10.111.180"}
                bfd_status: {diagnostic="No Diagnostic", flap_count="1", forwarding="true", remote_diagnostic="No Diagnostic", remote_state=up, state=up}
        Port ovn-d8eec7-0
            Interface ovn-d8eec7-0
                type: geneve
                options: {csum="true", key=flow, remote_ip="10.10.111.138"}
                bfd_status: {diagnostic="No Diagnostic", flap_count="1", forwarding="true", remote_diagnostic="No Diagnostic", remote_state=up, state=up}
        Port ovn-f4d136-0
            Interface ovn-f4d136-0
                type: geneve
                options: {csum="true", key=flow, remote_ip="10.10.111.194"}
                bfd_status: {diagnostic="No Diagnostic", flap_count="1", forwarding="true", remote_diagnostic="No Diagnostic", remote_state=up, state=up}
        Port patch-br-int-to-provnet-0c21d1e2-0d15-4467-bbcf-8d7d9c13549f
            Interface patch-br-int-to-provnet-0c21d1e2-0d15-4467-bbcf-8d7d9c13549f
                type: patch
                options: {peer=patch-provnet-0c21d1e2-0d15-4467-bbcf-8d7d9c13549f-to-br-int}
        Port ovn-6e4b94-0
            Interface ovn-6e4b94-0
                type: geneve
                options: {csum="true", key=flow, remote_ip="10.10.111.197"}

There doesn't appear to be any errors in /var/log/containers/neutron/ovn-metadata-agent.log logs, I'm unsure on how to proceed with further debugging of this issue.

Version-Release number of selected component (if applicable):
RHOS-16.1-RHEL-8-20201021.n.0

How reproducible:
Always

Steps to Reproduce:
1. Deploy OVN-DPDK + SR-IOV setup with DVR disabled
2. Spawn guest instances
3. Attempt to access nova metadata service via network

Actual results:
Nova metadata service is unreachable

Expected results:
Nova metadata service is reachable

Additional info:
Will attach deployment templates and SOS report