Dan,
I
only now read your response. I think we are “mostly” in sync on this topic. I
agree on the cultural aspects (as per my previous post).
However,
you might have misinterpreted my reference to the “maturity index”. It was not
my intention that we should incorporate the maturity model into the blueprints.
I merely used it as an example of how one may determine the appropriateness or
relative maturity of a specific SOA implementation.
Regards
Theo
From:
[mailto:]
Sent: Thursday, October 27, 2005
12:57
To: ; Beack, Theo;
; ;
Cc:
Subject: RE: [soa-blueprints]
Anti-Blueprints
Theo,
I'll
have to agree with Steve and Marc on this one as well.
Looking at what the problems are within existing SOA (or pseudo SOA)
helps to establish what a best practice or pattern should
address.
The
cultural barrier is something that needs to be addressed and if developers have
a solid blueprint to start from it makes their life a bit
easier.
All
the points you brought up around the problems within current web service
implementations are things that need to be addressed by a
blueprint.
Really
not sure if the maturity index is really something addressed by a
blueprint.
You
could apply some maturity criteria against the blueprint but a blueprint in
itself should be the maturity analysis.
For
instance maturity criteria could be:
- Your
services that adhere to various patterns within the Oasis SOA
blueprints
- You
have a management tools/policies in place that manage your
services
- You
are adhere to the Oasis SOA reference model within your SOA
- You
use various WS-* specs (not to say WS approach is the only way to
go) or other industry specs
- You
have a governance and standards body to help shape the SOA
environment
- You
have a SOA based definition process (could be based on Cap..'s
work)
-
Etc...
Dan
-----Original Message-----
From: Davies Marc
[mailto:]
Sent: Thursday, October 27, 2005
3:52 AM
To: Beack, Theo; Jones, Steve G; Ken Laskey; Miko
Matsumura
Cc:
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
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From: Beack, Theo
[mailto:]
Sent: 27 October 2005 05:15
To: Jones, Steve G; Ken Laskey; Miko
Matsumura
Cc:
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:]
Sent: Tuesday, October 25, 2005
17:12
To: Ken Laskey; Miko
Matsumura
Cc:
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:]
Sent: 25 October 2005 21:47
To: Miko Matsumura
Cc:
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:]
Sent:
Tuesday, October 25, 2005 12:57 PM
To:
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:]
Sent: Tuesday, October 25, 2005
12:41 PM
To: ;
;
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:
[mailto:]
Sent: Tuesday, October 25, 2005
11:54 AM
To: ;
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:]
Sent: Tuesday, October 25, 2005
11:21 AM
To:
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
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txt: +44 (0) 7891157026
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