The problem was solved.
It was due to the underlying macvtap bridge.

On Sat, 15 Aug 2020 at 17:38, Reza Bakhshayeshi <reza.b2008@gmail.com> wrote:
Hi all,

I've set up OpenStack Ussuri with OVN networking manually, VMs can ping each other through an internal network. I've created a provider network with valid IP subnet, and my problem is VMs don't have internet access before and after assigning floating IP.
I've encountered the same problem on TripleO (with dvr), and I just wanted to investigate the problem by manual installation (without HA and DVR), but the same happened.
Everything seems working properly, I can't see any error in logs, here is agent list output:

[root@controller ~]# openstack network agent list
+--------------------------------------+------------------------------+------------------------+-------------------+-------+-------+-------------------------------+
| ID                                   | Agent Type                   | Host                   | Availability Zone | Alive | State | Binary                        |
+--------------------------------------+------------------------------+------------------------+-------------------+-------+-------+-------------------------------+
| 1ade76ae-6caf-4942-8df3-e3bc39d2f12d | OVN Controller Gateway agent | controller.localdomain | n/a               | :-)   | UP    | ovn-controller                |
| 484f123f-5935-44ce-aee7-4102271d9f11 | OVN Controller agent         | compute.localdomain    | n/a               | :-)   | UP    | ovn-controller                |
| 01235c13-4f32-4c4f-8cf6-e4b8d59a438a | OVN Metadata agent           | compute.localdomain    | n/a               | :-)   | UP    | networking-ovn-metadata-agent |
+--------------------------------------+------------------------------+------------------------+-------------------+-------+-------+-------------------------------+

On the controller I got br-ex with a valid IP address. here is the external-ids table on controller and compute node:

[root@controller ~]# ovs-vsctl get Open_vSwitch . external-ids
{hostname=controller.localdomain, ovn-bridge=br-int, ovn-cms-options=enable-chassis-as-gw, ovn-encap-ip="10.0.0.11", ovn-encap-type=geneve, ovn-remote="tcp:10.0.0.11:6642", rundir="/var/run/openvswitch", system-id="1ade76ae-6caf-4942-8df3-e3bc39d2f12d"}

[root@compute ~]# ovs-vsctl get Open_vSwitch . external-ids
{hostname=compute.localdomain, ovn-bridge=br-int, ovn-encap-ip="10.0.0.31", ovn-encap-type=geneve, ovn-remote="tcp:10.0.0.11:6642", rundir="/var/run/openvswitch", system-id="484f123f-5935-44ce-aee7-4102271d9f11"}

and I have:

[root@controller ~]# ovn-nbctl show
switch 72fd5c08-6852-4d7e-b9b4-7e0a1ccdd976 (neutron-b8c66c3d-f47a-42a5-bd2d-c40c435c0376) (aka net01)
    port cf99f43b-0a18-4b91-9ca5-b6ed3f86d994
        type: localport
        addresses: ["fa:16:3e:d0:df:82 192.168.0.100"]
    port 4268f511-bee3-4da0-8835-b9a8664101c4
        addresses: ["fa:16:3e:35:f2:02 192.168.0.135"]
    port 846919e8-cde5-4ba3-b003-0c06e73676ed
        type: router
        router-port: lrp-846919e8-cde5-4ba3-b003-0c06e73676ed
switch bb22224e-e1d1-4bb2-b57e-1058e9fc33a7 (neutron-9614546f-b216-4554-9bfe-e8d6bb11d927) (aka provider)
    port 2f05c7bc-ad0f-4a41-bbd8-5fef1f5bfd2c
        type: localport
        addresses: ["fa:16:3e:17:7b:5b  X.X.X.X"]
    port provnet-9614546f-b216-4554-9bfe-e8d6bb11d927
        type: localnet
        addresses: ["unknown"]
    port 23fcdc9d-2d11-40c9-881e-c78e871a3314
        type: router
        router-port: lrp-23fcdc9d-2d11-40c9-881e-c78e871a3314
router 0bd35585-b0a3-4c8f-b71b-cb87c9fad060 (neutron-8cdcd0d2-752c-4130-87bb-d2b7af803ec9) (aka router01)
    port lrp-846919e8-cde5-4ba3-b003-0c06e73676ed
        mac: "fa:16:3e:4d:c3:f9"
        networks: ["192.168.0.1/24"]
    port lrp-23fcdc9d-2d11-40c9-881e-c78e871a3314
        mac: "fa:16:3e:94:89:8e"
        networks: ["X.X.X.X/22"]
        gateway chassis: [1ade76ae-6caf-4942-8df3-e3bc39d2f12d 484f123f-5935-44ce-aee7-4102271d9f11]
    nat 8ef6167a-bc28-4caf-8af5-d0bf12a62545
        external ip: " X.X.X.X "
        logical ip: "192.168.0.135"
        type: "dnat_and_snat"
    nat ba32ab93-3d2b-4199-b634-802f0f438338
        external ip: " X.X.X.X "
        logical ip: "192.168.0.0/24"
        type: "snat"

I replaced valid IPs with X.X.X.X

Any suggestion would be grateful.
Regards,
Reza