openstack team mailing list archive

[Trinath Somanchi <trinath.somanchi@xxxxxxxxx>]

Hi Guys-


I have found the solution to my Second Doubt

Link: http://docs.openstack.org/developer/nova/devref/rpc.html

and Thanks Emilien for clearing my 3rd Doubt.

But still in need of help.

Can you any one validate my understanding with the data flow in
Nova+Quantum scenario for bringing up the VM instances.

*[Trinath] *The flow as follows


   1. Upon receiving an REST call from Horizon, Nova API collected the
   Networking information from the nova_network and prepares an JSON formatted
   request and update the AMQP Queue.
   2. AMQP sends an Async cast to Nova Compute. Upon receiving the cast,
   Nova Compute issues _create_instance and updates the AMQP queue. AMQP queue
   sends an Async cast to Scheduler.
   3. Upon receiving the cast, Scheduler selects the Compute Node and send
   an async cast to the node. Node using the info in the queue using libvirt
   brings up the instance.
   4. Quantum-Agent at NODE updates the DB at controller with the Vlan
   tagged Port-Vif details.
   5. Quantum-Agent at Controller upon reading the DB on Vlan tagged
   Port-Vif details creates Gateway interfaces in the OVS integration bridge
   so that controller can access the VM's present in remote host.



On Mon, Jul 30, 2012 at 11:52 AM, Trinath Somanchi <
trinath.somanchi@xxxxxxxxx> wrote:

> Hi-
>
> I'm now viewing the code of Openstack from a top level to understand the
> process flow of the commands and messages in the system.
>
> I have the following doubts.
>
> [1] What is the role of Quantum-Agent in Controller and Node. How will the
> "gw-" and "tap-" interface and ports are created in Controller and Host
> integration bridge of ovs.
>
> This is how I understand from my study.
>
> *[Trinath] *The flow as follows
>
>
>    1. Upon receiving an REST call from Horizon, Nova API collected the
>    Networking information from the nova_network and prepares an JSON formatted
>    request and update the AMQP Queue.
>    2. AMQP sends an Async cast to Nova Compute. Upon receiving the cast,
>    Nova Compute issues _create_instance and updates the AMQP queue. AMQP queue
>    sends an Async cast to Scheduler.
>    3. Upon receiving the cast, Scheduler selects the Compute Node and
>    send an async cast to the node. Node using the info in the queue using
>    libvirt brings up the instance.
>    4. Quantum-Agent at NODE updates the DB at controller with the Vlan
>    tagged Port-Vif details.
>    5. Quantum-Agent at Controller upon reading the DB on Vlan tagged
>    Port-Vif details creates Gateway interfaces in the OVS integration bridge
>    so that controller can access the VM's present in remote host.
>
> Please update/correct with the pitfalls in my understanding outlined above.
>
>
> [2] How AMQP (using RabbitMQ server) work, mean to say. How Controller
> communicates with the Node for creating an Virtual instance in view of
> AMQP. Wanted to be more clear on what Messages do Controller and Node
> exchange to create an Virtual Instance.
>
> *[Trinath]* I'm not good at AMQP. Can you kindly describe on how this
> works.
>
> [3] I have created a Public and Tenant specific network using "nova-manage
> network " command.
>
> For each Virtual Instance, I have seen a Public IP addr, and Tenant
> Specific IP Addr. For both IP addrs I'm unable to ping from NODE machine.
>
> Rather for the Tenant specific IP Addrs I'm able to ping from Controller
> but not the Public IP Addrs..
>
> Can any one guide me on what has happened in the way...
>
> Thanking you...
>
> --
> Regards,
> ----------------------------------------------
> Trinath Somanchi,
> +91 9866 235 130
>
>


-- 
Regards,
----------------------------------------------
Trinath Somanchi,
+91 9866 235 130