Open Stack

Flavio Percoco wrote:
> [...]
> Based on the feedback from the meeting[3], the current main concern is:
> 
> - Do we need a messaging service with a feature-set akin to SQS+SNS?
> [...]

I think we do need, as Samuel puts it, "some sort of durable
message-broker/queue-server thing". It's a basic application building
block. Some claim it's THE basic application building block, more useful
than database provisioning. It's definitely a layer above pure IaaS, so
if we end up splitting OpenStack into layers this clearly won't be in
the inner one. But I think "IaaS+" basic application building blocks
belong in OpenStack one way or another. That's the reason I supported
Designate ("everyone needs DNS") and Trove ("everyone needs DBs").

With that said, I think yesterday there was a concern that Zaqar might
not fill the "some sort of durable message-broker/queue-server thing"
role well. The argument goes something like: if it was a queue-server
then it should actually be built on top of Rabbit; if it was a
message-broker it should be built on top of postfix/dovecot; the current
architecture is only justified because it's something in between, so
it's broken.

I guess I don't mind that much zaqar being "something in between":
unless I misunderstood, exposing extra primitives doesn't prevent the
"queue-server" use case from being filled. Even considering the
message-broker case, I'm also not convinced building it on top of
postfix/dovecot would be a net win compared to building it on top of
Redis, to be honest.

-- 
Thierry Carrez (ttx)