[Hawkular-dev] Availability

[Heiko W.Rupp]

On 20 Mar 2015, at 17:42, John Sanda wrote:
> Great point about multiple resources. I have to therefore slightly 
> refine my previous statement. I think that the functionality belongs 
> on the agent. As I said in the agent discussions, I think that there 
> are use cases for different types of agents - embedded, c-located, and 
> remote. For the example of monitoring availability for a resource (or 
> resources) spanning several machines, I think it should be the job of 
> a remote agent. Maybe that remote agent is running inside the hawkular 
> server. I am not sure. They key though is that the approach is 
> consistent in terms of who is applying that availability function.

I have been talking about "cheap alert pre-computation" on the
agent in the past, and this certainly makes sense. But it also
opens a can of worms^w complexity, that we should not tackle
in the first place.

The other question is what do we do with raw-avail-data-sources,
that are not delivered by an agent we write, but e.g. via curl?

For now I propose to do the computation on the server side.
Attached image illustrates this. All incoming "raw" data (that should
be used for alerting / computed resource state)  is
* stored in e.g. Hawkular-Metrics
* run through the function that e.g. determines that a http status code 
500 means DOWN
    or a duration > 300ms means WARN
* the result of the function is then also stored and forwarded to 
alerting
    and other users.

We would of course need to provide default-functions, but with the 
possibility to
fine-tune them.
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