Subject: FW: [soa-blueprints] Anti-Blueprints
Hi Reza is experiencing technical difficulty so I have forwarded his post to the list as below... -----Original Message----- From: Reza Shafii [mailto:email@example.com] Sent: Thu 10/27/2005 6:05 PM To: Beack, Theo; Davies Marc; Jones, Steve G; Ken Laskey; Miko Matsumura Cc: firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints Theo et. al. II tend to agree with Theo in that I don’t believe the raw number of services alone can provide much of an indication with respect to the design of an SOA. IMHO, what is more important is the granularity of the service operations that form each enterprise service. If a service is formed of a large number of low level service operations that, in most cases, clients have to use in combination, then you probably have too many service operations for that service. In other words your services operations are too fine grained, since the combination of calls can be abstracted through a façade and exposed as a coarser grained service operation. If you combine the above premise with the fact that the operations of all services are not always defined by the same people within an organization, then you can conclude that in many cases you are likely to end up with services with varying degrees of operations granularity. Therefore, not even the total number operations within an enterprise can be a good indicator of SOA design flaws. I would therefore argue that in order to decide whether the right level of granularity is achieved, each service should be analyzed in and out of itself in the context of the service client’s use of that service. The anti-pattern might therefore be somewhere along the line of the following: A service that contains a set of operations that always have to be used in combination by its clients within a single transaction. Cheers, Reza _____ From: Beack, Theo [mailto:Theo.Beack@softwareagusa.com] Sent: Thursday, October 27, 2005 7:46 PM To: Davies Marc; Jones, Steve G; Ken Laskey; Miko Matsumura Cc: email@example.com Subject: RE: [soa-blueprints] Anti-Blueprints Hi Marc, I wrote that email quite early in the morning, so I was not as precise in my wording as I would have liked. Anyway, I would like to further qualify my statement with regards to the number of services. I don't consider the number of services to be an accurate indication of either a good or bad approach, *if taken at face value*. You need the appropriate context around the numbers to make sense of them. Let me use an example to illustrate. When city planners are working on a new city master plan, how do they determine whether a city or certain borough within that city might be overpopulated? How do they determine whether there is sufficient infrastructure and resources available to support the existing population? How do they determine whether the existing infrastructure can support future growth? Do they only look at the number of people in the city and then make a judgement call whether it is overpopulated or not and whether it can support future growth? I would venture to say that their calculations and models would be far more complex and incorporate a large number of different factors, in order to accurately determine the appropriate population size. As an example, if a certain city had a population of 3 million, would that be an indication that the city if overpopulated? It is difficult to say. If one knew that the city is Hamilton, MT one would be safe to assume that Hamilton would be wildly overpopulated. If the city on the other hand, was the borough of Manhattan one would be quite safe in assuming that the city is not overpopulated, due to the fact that it has adequate housing, transport infrastructure, utilities, water supplies, etc. . . . I think some of same principles apply to SOA implementations. Organizations vary in size; their IT environments also vary in size and complexity. A small company of around $100M - $200M with an IT department of around 100 people and 10-20 different systems would most likely not require hundreds of services. If you told me that they had 400-500 services, then I would most likely question the appropriateness of this number of services. If the organization in question is a large multi-national corporation with revenues of several billion $, one can be certain that it will have a much larger IT infrastructure to support the business. The application ecosystem will be large, with a lot of complexity and integration requirements. If the number of services deployed is also within the 400-500 range, it would still be difficult for us to tell whether there are too many services and whether they are making good reuse of all these services. I think it would be prudent, in both cases, to investigate and do a proper analysis to determine whether good SOA design principles have been followed. So in summary; I agree that the number of services should be one of the factors that one need to incorporate into the analysis, while factoring in the context of what you know about the overall application infrastructure, complexity, integration requirements, etc. Regards Theo _____ From: Davies Marc [mailto:Marc.Davies@uk.fujitsu.com] Sent: Thursday, October 27, 2005 06:52 To: Beack, Theo; Jones, Steve G; Ken Laskey; Miko Matsumura Cc: firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints Sorry Theo but, I think Steve is on to something with anti-patterns and I *do* consider the number of services to give an indication of approach. In particular your comment: - it might even be a cultural barrier; developers might think using services is a waste of time and prefer to integrate their apps in another way …Implicitly indicates to me that (in that example) this is not an SOA environment. An SOA journey must have strong centralised (architectural) control ensuring developers do not just ‘do it’ how they think is the best way forward for “their” application (which in reality of course, isn’t their application – it’s the business’ application, a fault many of us have suffered from at some point in our careers, I’m sure :o) SOA is not WS (IMHO), SOA does mean strong Governance and adherence to standards, and this may frequently upset Developers! M. Marc Davies Fujitsu Business Unit Chief Technology Officer Architecture & Design Group Core Services Mobile: +44 (0) 7867 825118 E-mail: email@example.com Telephone: -Hot Desking- http://uk.fujitsu.com <http://uk.fujitsu.com/> This e-mail is only for the use of its intended recipient. Its contents are confidential and may be privileged. Fujitsu Services does not guarantee that this e-mail has not been intercepted and amended or that it is virus-free. _____ From: Beack, Theo [mailto:Theo.Beack@softwareagusa.com] Sent: 27 October 2005 05:15 To: Jones, Steve G; Ken Laskey; Miko Matsumura Cc: firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints I don't consider the number of services to be an accurate indication of either a good or bad approach. I think that one has to be more precise in measuring the relative maturity of the services that exist. Factors that can help one determine the "maturity index" of the SOA implementation might include: - level of reuse, - scope of the services, - service granularity, - adherence to architectural blueprints, - compliance with standards, etc. This is not a comprehensive list and one can take different views on how to measure the maturity of the services implementation, but the point I'm trying to illustrate is that one has to look at this from different angles in order to determine whether the approach which has been followed is a good or "bad" one. The statement “We’ve got hundreds of web services and it hasn’t helped us at all” is only a symptom of a potentially larger (or real) problem. The lack of reuse can be caused by factors such as: - developers might find it difficult to find the appropriate services, - several conflicting services might exist that provides similar functionality, - instability or lack of performance of services & infrastructure might cause developers to abandon the use of services, - it might even be a cultural barrier; developers might think using services is a waste of time and prefer to integrate their apps in another way In my experience many organizations create services without doing any planning. Many tools allow them to do this in a very easy manner and developers could easily created a large collection of services, without any planning. Following a good services design approach might be an important step to create truly reusable services. Determining the purpose of the service, who the primary consumers will be, usage patterns, interfaces required for the various consumers, service security, documentation, proper metadata, etc. all of these aspects of a service should be considered and might play an important part in making it a usefull and widely used service. Regards Theo _____ From: Jones, Steve G [mailto:email@example.com] Sent: Tuesday, October 25, 2005 17:12 To: Ken Laskey; Miko Matsumura Cc: firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints In other words has someone just “right-clicked” on a JavaBean (or C# object) and selected “Create Web Service” from the menu, or was there actually planning and intent? I’ve actually seen organisations where just this sort of exercise has been undertaken creating the thousands of web services problem. Number is part of the issue, its indicative of a bad approach when organisations create thousands of DISTINCT (as opposed to instances) of web services. But the Service should have a qualitative impact on the “real-world” or provide a useful function (e.g. mathematical calculation) this stuff is in the SOA-RM as being the basis of service. In terms of numbers I’d say that volume is an important indicator of bad practice, not a definitive guide but its getting a more and more common statement “We’ve got hundreds of web services and it hasn’t helped us at all”. Clearly its possible to have lots of top quality services, in the same way as in theory its possible for people to write decent multi-threaded code but in practice both are normally indicators of problems. Steve _____ From: Ken Laskey [mailto:email@example.com] Sent: 25 October 2005 21:47 To: Miko Matsumura Cc: firstname.lastname@example.org Subject: Re: [soa-blueprints] Anti-Blueprints The question is less one of number than independence. Does the original interface (method call) provide a capability that is useful beyond the object with which it is connected and can it be used without being part of a sequence with other methods from the same object? Ken On Oct 25, 2005, at 4:10 PM, Miko Matsumura wrote: Good feedback Duane. This is a good topic, thanks for introducing it, Steve. The number of services *is* a quantitative measure, but perhaps not a very helpful one? =) I'm pretty sure there's an antipattern here, and I think perhaps there could be some kind of way to assess this. I think another variable in this mix is the extent to which the registry repository in question can help with respect to discovery and classification as well as governance. The thing that worries me is when I see people assuming that fine grained (object level) services will be reused, when the reality is that OO didnt generate that much reuse from even the guy in the next cubicle, let alone across the company or across the planet. I think this is less of a gross number of services antipattern so much as a coarse-grained vs fine-grained antipattern... Best, Miko From: Duane Nickull [mailto:email@example.com] Sent: Tuesday, October 25, 2005 12:57 PM To: firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints I disagree with this anti-pattern. I am not sure that the number of services is really a quantitative measure of SOA. A grid computing cluster administrator may be able to rationalize such behavior, although it may seem absurd in other areas such as Amazon deploying a service for each book it carries vs. deploying one service that allows the consumer to parameterize the book title. Perhaps a better measure would be the development of some test criteria to ascertain whether a contemplated service is a good candidate for repurposing beyond a small number of consumers. This should be based on alignment with LOB and presumably different implementers will have different criteria for quantifying such. Duane From: Miko Matsumura [mailto:email@example.com] Sent: Tuesday, October 25, 2005 12:41 PM To: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints I just added a "microservice" antipattern where programmers put 10000000 WSDLs into a registry just because their IDE lets them do so. Miko From: email@example.com [mailto:firstname.lastname@example.org] Sent: Tuesday, October 25, 2005 11:54 AM To: email@example.com; firstname.lastname@example.org Subject: RE: [soa-blueprints] Anti-Blueprints Steve, Good idea. I put up the first drafts of them at: http://blueprints.jot.com/WikiHome/SOA+Anti-Patterns/SOA%20Anti-Patterns Let me know if I correctly eloborated and named them for you. Thanks, Dan -----Original Message----- From: Jones, Steve G [mailto:email@example.com] Sent: Tuesday, October 25, 2005 11:21 AM To: firstname.lastname@example.org Subject: [soa-blueprints] Anti-Blueprints The SOA Blueprints will lay down a “best practice” set of guidelines and templates for delivering SOA. This will definitely be a positive thing and help expand and firm up people’s understanding of SOA. One thing that the group states that it will do is define standards and guidelines, does this mean that allied to our blueprints we must also consider the “anti-blueprints” (analogous to anti-patterns) that must be avoided. So for instance focusing on process over service (bad), only thinking of web services (bad) etc etc. Defining the blueprints give guidance towards success criteria, but should we also give guidance on failure criteria for acceptance of a system as being “SOA”. Not sure whether this should be in the TC as its laying down best practice, and not to increase the already large workload… but it needs to be somewhere. My top 5 are 1) If you’ve started with an enterprise “best practice” process map you are NEVER going to be SOA and 90% probability your system will be inflexible or fail. 2) Web Service point to point is STILL point to point, doing a bad practice in XML doesn’t make it better 3) Splitting into two separate tiers of Service and Process with separate rules and governance results in divergent solutions 4) Creating “business” services based on the belief that IT understands the business results in services that meet neither IT nor business goals 5) Building your own proprietary XML-RPC stack to give yourself “control“ The last could still be SOA from one perspective, but I’ve yet to see it done well when the driver was a belief that its better done in house than using standards. When we get the official Wiki it could be something to document via that route. Steve ___________________________________________________________ Steve Jones | Capgemini CTO, Application Development Transformation T +44 870 906 7026| 700 7026| www.capgemini.com m: email@example.com txt: +44 (0) 7891157026 Join the Collaborative Experience ___________________________________________________________ This message contains information that may be privileged or confidential and is the property of the Capgemini Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message. ------------------------------------------------------------------------------------------ Ken Laskey MITRE Corporation, M/S H305 phone: 703-983-7934 7515 Colshire Drive fax: 703-983-1379 McLean VA 22102-7508 This message contains information that may be privileged or confidential and is the property of the Capgemini Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message.