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ovs_quantum_agent: ovs-ofctl error br-int is not a bridge or a socket

asked 2012-03-06 11:13:24 -0500

sumit-sngpt gravatar image

When I execute ovs_quantum_agent script to run Openvswitch agent for quantum, I get output from ovs-ofctl as "br-int is not a bridge or a socket". Is this an error? Btw, I still see the agent as an active process but I don't see the agent to use existing MYSQL database records created by quantum plugins and that communicating to local openvswitch setup.

bash $ sudo python ./ /etc/quantum/plugins/openvswitch/ovs_quantum_plugin.ini
ovs-ofctl: br-int is not a bridge or a socket ovs-ofctl: br-int is not a bridge or a socket

Thanks in advance, Sumit

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answered 2012-03-06 18:03:41 -0500

asomya gravatar image


The integration bridge is defined in the ovs_quantum_plugin.ini file.

This is the name of the OVS integration bridge. There is one per hypervisor.

The integration bridge acts as a virtual "patch port". All VM VIFs are

attached to this bridge and then "patched" according to their network


integration-bridge = br-int

Has this bridge been created on your host? You might need to create is manually using:

sudo ovs-vsctl --no-wait add-br br-int

The database communication params are also defined in the same ini file, verify if the settings match your mysql installation and the database exists:


This line MUST be changed to actually run the plugin.

Example: sql_connection = mysql://root:nova@

Replace above with the IP address of the database used by the

main quantum server. (Leave it as is if the database runs on this host.)

sql_connection = mysql://root:nova@localhost/ovs_quantum

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answered 2012-03-07 07:13:22 -0500

sumit-sngpt gravatar image

hi Arvind,

Thanks for your reply. I checked the integration bridge 'br-int' is properly defined in ovs_quantum_plugin.ini file.

Also, the bridge 'br-int' is already created and existing in my machine.

bash$ sudo ovs-vsctl --no-wait add-br br-int ovs-vsctl: cannot create a bridge named br-int because a bridge named br-int already exists

The database is also exists and well configured.

The plugin of openvswitch for quantum is running fine and I don't have any issues with it , in the way it is updating the mysql database properly but then what is the work of its agent ''? I believe it should read the mysql database created by the quantum plugins and do something with openvswitch. Can you help me with this agent usage? The agent process is running but not doing anything.

bash$ ps auxxww | grep ovs_quantum root 19183 0.0 0.0 5796 1672 pts/1 S+ Mar06 0:00 sudo python ./ /etc/quantum/plugins/openvswitch/ovs_quantum_plugin.ini root 19189 0.2 0.5 27856 12024 pts/1 S+ Mar06 3:15 python ./ /etc/quantum/plugins/openvswitch/ovs_quantum_plugin.ini

bash$ sudo ovs-vsctl show 028dd83e-bf6a-4b77-894b-5424604e9c36 Bridge br-int Port br-int Interface br-int type: internal Port "eth0" Interface "eth0"

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answered 2012-03-07 17:43:26 -0500

asomya gravatar image

Hey Sumit

Since quantum runs as a single service on a single host and not as a distributed service like nova-network etc; the ovs agent instead runs on each host and does the actual underlying configuration like adding tap interfaces and gateways on hosts.

It does scan the database periodically for and additions/removals of ports and networks.

Have you tried starting any VM's in your cloud? the agent only comes into play when ports and vlans have to added/removed to the bridge.

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Asked: 2012-03-06 11:13:24 -0500

Seen: 1,035 times

Last updated: Mar 07 '12