[openstack-dev] [Heat] Continue discussing multi-region orchestration

Zane Bitter zbitter at redhat.com
Sat Nov 16 08:20:32 UTC 2013

On 16/11/13 00:07, Georgy Okrokvertskhov wrote:
> Hi,
> With slight modifications of (2) one can benefit of availability:
> 1. There should not be a master node. Each heat engine should be able to
> act as a master if someone asks it to deploy a template. Current master
> engine will be responsible to contact other engines and pass them the
> same template and wait for confirmation.
> 2. Each Heat engine instance receives whole template but deploys only
> resources which are designated to engine's zone
> This will provide all benefits of availability as all engines will keep
> a copy of a template and you can update template by using any heat
> engine. For example if heat engine in region 1 is down or whole site 1
> is down you can update a template with new region settings and update it
> with using heat engine in region 2.

What you're describing is basically Option (5) - build a globally 
highly-available distributed Heat engine. I don't see how you can 
describe that as a "slight modification", it's an entire research 
project that is probably  bigger in scope than everything else we have 
to do in Icehouse put together. As stated previously, I am heavily -2 on 
this idea.

> The multi-region support proposal contains information and proposal for
> "what" and "how" but does not describe "why". If we talk just about
> multi-region placement support then option (4) works fine. If there is
> an intension to build a solution for HA, DR, elastic scalability for
> spike loads then we need to keep availability as a part of a design.

I think we should build a system that allows our users to manage 
highly-available global apps, not try to build one ourselves.


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