[openstack-dev] [Openstack] Making the RPC backend a required configuration parameter

Russell Bryant rbryant at redhat.com
Thu Aug 9 17:22:15 UTC 2012

CC'ing openstack-dev since that is a more appropriate list for this

On 08/08/2012 04:35 PM, Eric Windisch wrote:
> I believe that the RPC backend should no longer have any default.

I disagree and my reason is fairly straight-forward.  Changing the
default will break existing configurations.  The benefits must outweight
that.  I don't see enough benefit to outweigh any inconvenience to users.

> Historically, it seems that the Kombu driver is default only because it existed before all others and before there was an abstraction. With multiple implementations now available, it may be time for a change.
> Why?
> * A default skews the attitudes and subsequent architectures toward a specific implementation
> * A default skews the practical testing scenarios, ensuring maturity of one driver over others.

I don't think these are true.

> * The kombu driver does not work "out of the box", so it is no more reasonable as a default than impl_fake.

My issue is that existing configuration files and configuration examples
are broken by this change.

I also don't understand why having a default that doesn't work for
anyone makes any sense.

> * The RPC code is now in openstack-common, so addressing this later will only create additional technical debt.

I don't feel that it's something that ever *needs* to be addressed, so
it's not technical debt.

Russell Bryant

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