Why Enterprise Architecture Usually Sucks.

Why Enterprise Architecture
Usually Sucks.
Phillip Calçado
ThoughtWorks
http://fragmental.tw

Saturday, 11 September 2010

1.Conway-Driven Architecture
2.Architecture-Driven Business


1. Conway-Driven Architecture

“Any organisation that designs a
system will inevitably produce a
design whose structure is a copy of
the organisation's communication
structure.”
-Melvin Conway


team a
team c

team b


system
a
system
c

system
b


system
a doesn’t
trust

system
c
doesn’t
trust

doesn’t
trust

system
b


system
a
system
c
legacy billing
database system y
x

inventory
system z
system
b hr
system w

portal s


can I have
this feature?
pretty please?


LOL r u crazy?


This “small”
system
a change means...
system
c
legacy billing
database system y
x

inventory
system z
system
b hr
system w

portal s


This “small”
system
a change means...
system
c
legacy billing
database system y
x
change
inventory
system z
system
b hr
system w

portal s


This “small”
system
a change means...
system
c
legacy billing
database system y
x
change
inventory
system z
system
changeb hr
system w

portal s


This “small”
system
a change means...
system
c
legacy billing
database system y
x
change
inventory
change system z
system
changeb hr
system w

portal s


This “small”
system
a change means...
change system
c
legacy billing
database system y
x
change
inventory
change system z
system
changeb hr
system w

portal s


This “small”
system change
a change means...
change system
c
legacy billing
database system y
x
change
inventory
change system z
system
changeb hr
system w

portal s


This “small”
system change
a change means...
change system
c
legacy billing
database system y
x
change change
inventory
change system z
system
changeb hr
system w

portal s


“I don’t understand why things
are so hard around here!”
“IT doesn’t deliver; we need more
people. Get me some consultants!”
“In-house is too complicated,
let’s buy a package!”
“We are too slow. We have
to become agile! ”

2. Architecture-Driven Business

“Developers have to translate for domain
experts. Domain experts translate between
developers and still other experts.
Developers even translate for each other.
The indirectness of communication conceals
the formation of schisms. This leads to
unreliable software that doesn't ﬁt together.”

-Eric Evans

IT always wins.


IT always wins.

We need invoices to
be available in our
sales channel to our
customers


IT always wins.

We need
invoice.xsds to be
available in our
portlets to our
contacts


developer’s kingdom

business’ nightmare

business’ developer’s
Oracle Invoice Server +
Invoicing PDF Printing Service +
SAP
Identity Manager +
Customer mapping CUS_SYS_01 Database +
CRM
CMS + E-Commerce
Sale Server + Warehouse
System


“How did we end up with
three CRMs again?”
“These customers are in another
database. We can create a service
for that...”
“This may be a simple change
for the business but in our end
it’s complicated!”

Some Suggestions


1.Don’t try to break the law
2.Design principles are fractal
3.Domain-Driven Architecture


system
a
system
c

system the
b
governance
group

system
a
system
c

system the
b
governance
group bottleneck


create
one
project team
with
people
from different
departments

system a
Attribute
Attribute
Operation
Operation system c
Attribute
Attribute
Operation
billing system y Operation
legacy Attribute
database Attribute
x Operation
Operation
inventory system z
Attribute
system b Attribute
Attribute Operation
Attribute Operation
Operation hr system w
Operation Attribute
Attribute
Operation
portal s
Attribute Operation
Attribute
Operation
Operation

•Layers
•Cohesion
•Coupling
•Dependency Injection
•...
still applies


big bang
mapping


Adopt Layers

} Business
Services

} Services
Infrastructure


Adopt Layers

Business
Vocabulary
}
(and Business Logic)
Business
Services
Technical
Vocabulary
(and no Business
Logic)
} Services
Infrastructure


Adopt Layers

little
mapping


Good Architectures support
and are driven by the business

Bad Architectures require the
business to change

What’s easy to change in the business
model should be easy to change in your
architecture

References
•http://www.melconway.com/research/
committees.html
•http://fragmental.tw/2009/02/24/what-is-a-
service/
•http://fragmental.tw/2010/08/17/thoughts-on-
abstractions-part-1-%E2%80%93-abstractions-
everywhere/
•http://fragmental.tw/2010/09/06/thoughts-on-
abstractions-part-2-abstractions-in-your-domain/
•http://fragmental.tw/2010/03/22/nevermind-
domain-driven-design/

Why Enterprise Architecture Usually Sucks.

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