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From Matthieu Morel <>
Subject Re: Adapter and PE in one Cluster
Date Wed, 10 Oct 2012 08:35:49 GMT
Our initial strategy of having multiple apps on the same logical cluster 
resulted in a lot of complexity for the implementation (classloading) 
and for operations (lifecycle, deployment).

As a consequence we opted for a simpler solution where there is only 1 
app per logical cluster. And we added a complementary mechanism for 
inter-app communications.

If you have apps that you used to deploy concurrently on the same 
logical cluster, you'll just need to define new logical clusters (of 
arbitrary dimensions) and deploy 1 app per logical cluster. Each S4 node 
belongs to a single logical cluster, which you specify when starting the 



On 10/10/12 9:59 AM, Shailendra Mishra wrote:
> Matthieu - One more related question, earlier I was able to deploy a
> number of apps in a single cluster instance but now after deploying
> the first app. when I try to deploy the second one I get the message
> blah! app already deployed. Is this by design or has the syntax of
> deploy changed in version .50. - Shailendra
> On Wed, Oct 10, 2012 at 12:52 AM, Matthieu Morel <> wrote:
>> - One reason for separating S4 app and adapter is so that the adapter only
>> focuses on converting external streams into streams of S4 events, while the
>> other S4 app(s) focus on business logic
>> - Another reason is that the adapter benefits from properties of S4 apps, in
>> particular scalability, being an S4 application itself.
>> - Last, using separate clusters for separate apps allows independent
>> deployment and administration.
>> However, you may as well implement some business logic in the adapter app
>> itself. It really depends on the complexity of the app. Implications on
>> static load balancing are really dependent upon the stream and the
>> application.
>> Hope this helps,
>> Matthieu
>> On 10/10/12 8:26 AM, Frank Zheng wrote:
>>> Hi All,
>>> Why do we need to put adapter and PE in separated clusters now?
>>> Is it possible to put adapter and PE nodes in one cluster?
>>> And how to do load balancing when adapter and PE nodes are in the same
>>> cluster?
>>> Thanks
>>> Yu

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