Neutron tags Open vSwitch port with vlan ID 4095

This document (7017648) is provided subject to the disclaimer at the end of this document.


SUSE OpenStack Cloud 5


A new instance in SUSE OpenStack Cloud deployed with Open vSwitch
doesn't get an IP address due to DHCP port being tagged with vlan 4095.


On control or network node, depending on which one the neutron barclamp
has been applied to, you can see the port that was tagged with vlan ID 4095.

1.) Find Open vSwitch port name

root@d52-54-00-63-29-7c:~ # ovs-vsctl show
        Port "tap894320e4-ea"
            tag: 4095
            Interface "tap894320e4-ea"
                type: internal

2.) Find Neutron port ID

root@d52-54-00-63-29-7c:~ # neutron port-list | grep 894320e4-ea
| 894320e4-ea03-4f22-a1a2-a983dab009de |      | fa:16:3e:87:ad:55 | {"subnet_id": "94177f4c-61e4-41a1-a3a9-d44dcdd0f52b", "ip_address": ""}   |

root@d52-54-00-63-29-7c:~ # neutron port-show 894320e4-ea03-4f22-a1a2-a983dab009de
| Field                 | Value                                                                                |
| admin_state_up        | True                                                                                 |
| allowed_address_pairs |                                                                                      |
| binding:host_id       | d52-54-00-63-29-7c                                                                   |
| binding:profile       | {}                                                                                   |
| binding:vif_details   | {}                                                                                   |
| binding:vif_type      | binding_failed                                                                       |
| binding:vnic_type     | normal                                                                               |
| device_id             | dhcpaf92b7c7-3515-5a53-b4d2-010fa0911f07-009454fd-5f57-4647-a5f5-ff2779449a7d        |
| device_owner          | network:dhcp                                                                         |
| extra_dhcp_opts       |                                                                                      |
| fixed_ips             | {"subnet_id": "94177f4c-61e4-41a1-a3a9-d44dcdd0f52b", "ip_address": ""} |
| id                    | 894320e4-ea03-4f22-a1a2-a983dab009de                                                 |
| mac_address           | fa:16:3e:87:ad:55                                                                    |
| name                  |                                                                                      |
| network_id            | 009454fd-5f57-4647-a5f5-ff2779449a7d                                                 |
| security_groups       |                                                                                      |
| status                | DOWN                                                                                 |
| tenant_id             | 2b3b58ef9bda46b1a6059b19ea710380                                                     |

binding:vif_type has value "binding_failed".

3.) Delete the neutron port from the database

neutron port-delete 894320e4-ea03-4f22-a1a2-a983dab009de

4.) Delete the port from Open vSwitch:

ovs-vsctl del-port br-int tap894320e4-ea

5.) Restart Neutron agents

In cluster:

   crm resource restart g-neutron-agents

On non-clustered network nodes:

   rcopenstack-neutron-l3-agent restart 
   rcopenstack-neutron-lbaas-agent restart
   rcopenstack-neutron-dhcp-agent restart
   rcopenstack-neutron-metadata-agent restart
   rcopenstack-neutron-openvswitch-agent restart

On systemd Linux:

   systemctl restart openstack-neutron-l3-agent
   systemctl restart openstack-neutron-lbaas-agent
   systemctl restart openstack-neutron-dhcp-agent
   systemctl restart openstack-neutron-metadata-agent
   systemctl restart openstack-neutron-openvswitch-agent

And re-launch the instance.


Vlan tag 4095 is used by the openvswitch-agent to mark "dead" ports.
Neutron tags such port with ID 4095 in integrration bridge(br-int)
if that port cannot be mapped to a neutron port.


This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7017648
  • Creation Date: 30-May-2016
  • Modified Date:03-Mar-2020
    • SUSE Open Stack Cloud

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