Concept/idea - proactive state change notification from oVirt/RHEV

Martin Povolny mpovolny at redhat.com
Mon Nov 12 09:53:06 UTC 2012


On Wed, Nov 07, 2012 at 08:38:31AM -0500, Hugh Brock wrote:
> On Wed, Nov 07, 2012 at 02:22:54PM +0100, Justin Clift wrote:
> > Just as an idea, oVirt/RHEV has hooks available that can be called
> > when instance states change (and for various other events).
> > 
> > Nicely, these hooks can be written in any language. (Python hooks
> > are definitely around)
> > 
> > So, how about the idea of us creating hooks which get installed on
> > oVirt/RHEV hosts, and proactively notify us (or deltacloud) when
> > instances change state.  So, we don't need to do polling.
> > 
> > Obviously it would have to be an optional approach, as it's an
> > intrusive measure for these hosts.  But it should allow for low
> > latency state change notification and better scalability, for
> > these places that need it.
> > 
> > Other provider types (ie vSphere?) might also have hooks too
> > (unsure).
> > 
> > Interesting idea?
> > 
> 
> Very interesting. I'd especially like to see what OpenStack has
> available in this area.
> 
> A whole separate effort for the Aeolus Project might ought to be a
> cross-cloud notification service that would poke the state machine. So
> you'd want for example to have a consistent API in front of:
> 
> * RHEV/oVirt hooks
> * OpenStack equivalent mechanism (whatever that is?)
> * CloudWatch
> * (maybe) an in-guest SNMP agent/trap?
> 

Having hooks for various providers to lower the amount of polling sounds
good to me as said during the conference.

And SNMP traps are surely a way that could be used by both the
provider-specific hooks and by in-host agents.

It would silent my cries for a message bus a bit ;-)

A "cool" thing that comes to my mind when talking about the buses was
writing a simple mobile app that would listen for change states on the
message bus and notify the admin/manager/whoever when something happens
in the cloud. I think I saw an image of a guy with a phone ringing in
his pocket on one of the slides during the conference.

Such app might be a "cool" showcase for having custom client connecting
to the message bus / message service / whatever.

This is a couple of lines on Android if you use AMQP (have such toy for
Asterisk notifications about incoming calls). In case of
SMTP it would be probably the same level of easy.

-- 
Martin Povolny <mpovolny at redhat.com>
tel. +420777714458



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