Will not database coupling endangers loose coupling achieved through RabbitMQ ?

Hi Roderick,

You are correct, and there are already plans to change this. We will be discussing it more at the design summit in a few weeks.

Vish

On Mar 28, 2011, at 6:05 AM, Roderick SUMBERS wrote:

> Question #150766 on OpenStack Compute (nova) changed:
> https://answers.launchpad.net/nova/+question/150766
>
> Description changed to:
> As stated in NOVA developer's guide "RabbitMQ sits between any two Nova
> components and allows them to communicate in a loosely coupled fashion".
>
> This seems a wonderful pattern to achieve scaleability/availability
> through inbuilt RabbitMQ mechanisms.
>
> BUT it looks to my (novice as related to OpenStack code) eyes that in
> several occasions (for example, between API and COMPUTE), only RPC call
> is routed through a MQ Message AND ASSOCIATED DATA IS COMITTED TO THE
> DATABASE by the message sender, and then RETRIEVED by the RPC Message
> consumer.
>
>
> As Complexity grows, coupling between components will raise through the database structure and shared data ; moreover, all components instance will have to share access to a central common database (oops for scalability).
>
> If we want to keep the good points of RabbitMQ oriented design,
> shouldn't we rework some code to ensure that the components communicate
> ONLY THROUGH RabbitMQ, and not through a common database ?
>
>
> Best regards to all of you who work on this wonderful project,
>
> Roderick SUMBERS.
>
> --
> You received this question notification because you are a member of Nova
> Core, which is an answer contact for OpenStack Compute (nova).

Thanks Vish,
 Is there any way to specifically track down/ be informed of the followups of this design topic (bug report ?) when discussion advances, or will you publish news in this thread?
R.

I have this flagged in my inbox to post something when there more information/blueprint, but in case i forget, try pinging in a couple weeks.

Vish

On Mar 28, 2011, at 11:41 AM, Roderick SUMBERS wrote:

> Question #150766 on OpenStack Compute (nova) changed:
> https://answers.launchpad.net/nova/+question/150766
>
> Status: Answered => Open
>
> Roderick SUMBERS is still having a problem:
> Thanks Vish,
> Is there any way to specifically track down/ be informed of the followups of this design topic (bug report ?) when discussion advances, or will you publish news in this thread?
> R.
>
> --
> You received this question notification because you are a member of Nova
> Core, which is an answer contact for OpenStack Compute (nova).

Are you guys discussing this internally until the design summit or would you be interested in suggestions from the masses?

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