Technical rants on distributed computing, high performance data management, etc. You are warned! A lot will be shameless promotion for VMWare products

Monday, July 31, 2006

SOA n GRID synergistic?

A colleague of mine brought this SOA vs GRID aricle to my attention .... ' provides some interesting data on this topic and debunks certain popularly held beliefs..'



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Here is my take on the SOA-GRID synergy or lack thereof in practice followed by a discussion on where and if a distributed cache can fit in such architectures …..

Clearly the whole business of service orientation is based on the fact that one discovers a service based on desired operation and other QoS considerations, before binding. Service clients are loosely coupled to service providers by definition.
In the case where service clients come and go, say, like with a portal service that aggregates information from 10 other services, each request could be routed through a intermediary that isolates client from directly connecting to the server. This could be the UDDI registry for instance.

You agree with this, ya? Now, the question is, in what percentage of such SOA architectures will one use a dynamic provisioning service (loosely a GRID)? i.e. every time I use the discovery service it may point me to a different server to get the request fulfilled. In many cases, the expected load might be very predictable or the service provider has to run on specific platform that is my legacy and cannot be deployed into a utility computing center. Folks talk about high availability and hence the need for the Grid, but, I think, that is just bull. All SOA architectures will use a JEE or .Net fa├žade and inherently be HA. So, basically, there is no case for a Grid in this situation.

But, more you look into the future, more likely I want my services to deployed using low cost commodity hardware, be bound by contracts on the QoS (availability and performance), forcing me to think about how my services can constantly be monitored and dynamically reprovisioned on the fly. The power of the Grid - well, actually a sophisticated provisioning and virtualization engine would become a necessity. I am not talking about a typical Grid solution, aka a compute grid - a scheduling engine.

In any case, like the who's who within the OGSA community would say, there is natural synergy between SOA and GRID. SOA is about how to connect services together to realize higher value (integration) and GRID is merely a deployment strategy for such services.

I thought, IBM was already on track to deliver on this promise within their WebSphere platform, circumventing the need for DS or EGO. Ahh! Who am I kidding?
Checkout Oracle's fusion strategy and how automatic provisioning and virtualization is integrated into 10G. Quite impressive.

Now, let me shift gear and see if and where a distributed caching solution fits in a SOA architecture .....

Where do databases and messaging solutions fit in? Just SOA architectures? Only in Compute Grid apps? Duh! everywhere. And, that is my position.
OK, here is the hiccup - again, SOA, by definition is all about getting apps (what do call this now … yeah! Services) talking to one another in a loosely coupled fashion. The service provider can change the underlying technology and behaviour any way it want and remains isolated from other services. I just have to make sure my contract is still intact. So, this cache thing breaks this, one could argue. The cynic would say 'I want a ESB bus that uses XML messaging not a bloody cache'.
Well, gentlemen, I got news for you. I think, all this loosely coupling stuff is baloney. Well, it holds water to a point, but no more.

The fact of the matter is, in real life, application models and yes, data models change and undergo significant enhancements. XML or no XML, your apps, if they need to talk to one another have to change.

You want to solve real problems, create a highly scalable, performant SOA architecture - use a memory based data fabric - An ESB designed for data intensive environments. You still want to use XML - shove data into the Enterprise Service Fabric (ESF) as XML. You don't like using APIs, but rather prefer the slippery SOAP (JAXM) route, use the web services interface.

And, now, fire storms have erupted in california ….

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