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How does neutron node update its agents to neutron DB?

asked 2015-11-04 08:03:45 -0600

Bharani gravatar image

I dont see any configuration about Database connection string in /etc/neutron/neutron.conf in neutron-node. I would like to understand how does it connect to the controller and updates status about its agent, like L3 agent, Metadata agent.

[ I understand we run neutron-db-manage in controller / neutron server but not on neutron/network node ].

I also see that in neutron.conf[ in network node] we dont specify where [ on which host] the Network server [neutron-server.service] is running. I would like to how the network node [neutron ] connects to the neutron-server.service ?

[ I am running kilo ]

Thanks in advance.

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answered 2015-11-05 03:43:39 -0600

dbaxps gravatar image

updated 2015-11-05 05:10:49 -0600

There is AMQP broker - service "rabbitmq-server" running on Controller.

Neutron agents (Network Node) communicate  with Neutron Server (Controller ) via message queues.

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I understand that only Neutron server can update the neutron DB. I would like to understand how agent status gets updated via message queue. And should it be Message Queue that this should happen ?

Bharani gravatar imageBharani ( 2015-11-05 05:31:12 -0600 )edit

answered 2015-11-04 22:30:27 -0600

Steven Su gravatar image

I think it's using message queue. E.g. In neutron.conf it has:

rpc_backend = rabbit

If you want dig it more you may have a look at: (

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Did you mean rabbit host? and the neutron node reports neutron server based on the rabbit_host ?

Bharani gravatar imageBharani ( 2015-11-05 01:26:22 -0600 )edit

Yes, if you look at the neutron.conf on controller node you will find it has same Message Queue server defined. Note that file has DB connection as well so it able to update Database.

Steven Su gravatar imageSteven Su ( 2015-11-05 05:53:18 -0600 )edit

ok steve, but the neutron node doesnt have a connection string, Only the controller/neutron server has the connection string in the neutron.conf

Bharani gravatar imageBharani ( 2015-11-05 06:11:18 -0600 )edit

What I understand is, just by having the Message Queue Server Name same in neutron.conf of the controller and neutron node updates the DB about its status ?

Bharani gravatar imageBharani ( 2015-11-05 06:13:33 -0600 )edit

Steve, I just noticed the connection string option in neutron.conf file in the neutron node. However I just dont see in the procedure in ( The connection string in neutron node.Will it be effective?

Bharani gravatar imageBharani ( 2015-11-05 07:53:29 -0600 )edit

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Asked: 2015-11-04 08:03:45 -0600

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Last updated: Nov 05 '15