[openstack-dev] [Zaqar][all] Zaqar will stay... Lots of work ahead

Flavio Percoco flavio at redhat.com
Mon Jun 1 08:40:03 UTC 2015

On 27/05/15 11:19 -0700, Clint Byrum wrote:
>Excerpts from Zane Bitter's message of 2015-05-27 10:40:48 -0700:
>> On 27/05/15 12:42, Clint Byrum wrote:
>> >
>> > == Crazy idea section ==
>> >
>> > One thing I never had a chance to discuss with any of the Zaqar devs that
>> > I would find interesting is an email-only backend for Zaqar. Basically
>> > make Zaqar an HTTP-to-email gateway. There are quite a few hyper-scale
>> > options for SMTP and IMAP, and they're inherently multi-tenant, so I'd
>> > find it interesting to see if the full Zaqar API could be mapped onto
>> > that. This would probably be more comfortable to scale for some deployers
>> > than Redis or MongoDB, and might have the nice side-effect that a deployer
>> > could expose IMAP IDLE for efficient end-user subscription,
>> Can you guarantee delivery end-to-end (and still get the scaling
>> benefits)? Because AIUI SMTP is only best effort, and that makes this
>> idea a non-starter IMHO.
>So yes and no. If you are going to set your Zaqar backend up to forward
>messages across the internet, then no, of course you cannot guarantee
>delivery. That is not what I am suggesting as the default configuration.
>However, in a closed system like a Zaqar backend SMTP would be, you
>have control over things like retries and bandwidth, so you can at
>least guarantee that if the intended destination is available, the
>message will make it there. If you have 100 SMTP servers enqueing for
>1000 destination queue servers, all with 1Gbit network between them,
>you'd simply set your retry interval much lower than for the internet,
>and allow infinite or very very high retries before giving up on messages.
>The scaling comes from the asynchronous queueing. One can have
>guaranteed delivery with asynchronous queueing.

Not such a crazy idea, TBH. This has come up in the past and as Monty
said the other day, he and I should sit down somewhere in EU and get a
PoC done.

That said, I think this would work better as a notifications publisher
- the SNS side of Zaqar - than a specific Zaqar storage backend. Right
now, we just have webhook publishers that push messages to registered
URLs. Instead of an URL, I'd expect there to be an smtp URL that Zaqar
would send messages to.

I guess that's what you were suggesting, right? Just want to make sure
we're talking about the same thing.


>OpenStack Development Mailing List (not for usage questions)
>Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe

Flavio Percoco
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20150601/6f72fb34/attachment.pgp>

More information about the OpenStack-dev mailing list