Slide deck from my keynote at the Software Development 2020 Conference in Breda, The Netherlands, June 2015. Micro-services and micro-services architecture are the next hype in software development. Websites and blogs are full of introducing posts, the first books are being written and the first conferences organized. There’s big promises of scalability, flexibility and replaceability of individual elements in your landscape. However, when you are knee deep in the mud as a software architect at an insurance, it is very hard to find help on how to design applications and components in a micro-services architecture. During this talk Sander Hoogendoorn, discusses the long and winding road the insurance company where he’s acting as the lead software architect has taken to implement their business processes in a micro-landscape. Sander will show how this company is modeling requirements in a micro-landscape using smart use cases, and will explain the difficulties and the lessons learned, using many real-life examples.

1. @aahoogendoorn
MICROSERVICES
THE GOOD, THE BAD AND THE UGLY
Sander Hoogendoorn
ditisagile.nl
Mentoring ▪ Consulting ▪ Training ▪ Agile ▪ Software architecture ▪ Code

2. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 2
@aahoogendoorn
www.ditisagile.nl
Sander Hoogendoorn
Me
 Dad
 Mentor, trainer, software architect, programmer
 Books, articles, conferences
Work
 Owner, ditisagile.nl
 CTO Klaverblad Verzekeringen
 [PTO Capgemini]
 [Global design authority agile Capgemini]
Web
 www.sanderhoogendoorn.com
 www.smartusecase.com
 www.speedbird9.com
 @aahoogendoorn
 sander@ditisagile.nl

3. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 3
@aahoogendoorn
www.ditisagile.nl

4. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 4
@aahoogendoorn
www.ditisagile.nl
On being a developer...

5. @aahoogendoorn
MONOLITHS
Hard to deliver, even harder to test and impossible to maintain

6. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 7
@aahoogendoorn
www.ditisagile.nl
Monoliths
Advantages
 A single (layered) architecture
 A single technology stack
 A single code base maintained by multiple teams
Disadvantages
 All parts are interconnected
 Many other systems are connected to your system
 Hard to change, hard to maintain
 Long time between releases, thereby increasing risks
 Slow innovation
 Hard to move to newer technologies
 Doesn’t scale very well
Product Account
Order Customer
Products Accounts
Orders Customers

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©2015 ditisagile.nl. All Rights Reserved 8
@aahoogendoorn
www.ditisagile.nl
Dependencies will kill you

8. @aahoogendoorn
A BRIEF HISTORY
OF COMPONENTS AND SERVICES

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©2015 ditisagile.nl. All Rights Reserved 10
@aahoogendoorn
www.ditisagile.nl
Client server

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©2015 ditisagile.nl. All Rights Reserved 11
@aahoogendoorn
www.ditisagile.nl
Component based development

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©2015 ditisagile.nl. All Rights Reserved 12
@aahoogendoorn
www.ditisagile.nl
Service oriented architecture

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©2015 ditisagile.nl. All Rights Reserved 13
@aahoogendoorn
www.ditisagile.nl
Microservices

13. @aahoogendoorn
MICROSERVICES
Beyond the hype?

14. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 15
@aahoogendoorn
www.ditisagile.nl
Microservices. Beyond the hype?

15. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 16
@aahoogendoorn
www.ditisagile.nl
Gartner hype cycle

16. @aahoogendoorn
MICROSERVICES
The clear benefits

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©2015 ditisagile.nl. All Rights Reserved 18
@aahoogendoorn
www.ditisagile.nl
BUTFIRST…ADEFINITION

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©2015 ditisagile.nl. All Rights Reserved 19
@aahoogendoorn
www.ditisagile.nl
Inshort,themicroservicearchitecturalstyleisanapproachtodevelopingasingleapplicationasasuiteofsmallservices,
eachrunninginitsownprocessandcommunicatingwithlightweightmechanisms,oftenanHTTPresourceAPI.
Theseservicesarebuiltaroundbusinesscapabilitiesandindependentlydeployablebyfullyautomateddeploymentmachinery.
Thereisabareminimumofcentralizedmanagementoftheseservices,whichmaybewrittenindifferentprogramminglanguages
andusedifferentdatastoragetechnologies.
MartinFowler

19. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 20
@aahoogendoorn
www.ditisagile.nl
Inshort,themicroservicearchitecturalstyleisanapproachtodevelopingasingleapplicationasasuiteofsmallservices,
eachrunninginitsownprocessandcommunicatingwithlightweightmechanisms,oftenanHTTPresourceAPI.
Theseservicesarebuiltaroundbusinesscapabilitiesandindependentlydeployablebyfullyautomateddeploymentmachinery.
Thereisabareminimumofcentralizedmanagementoftheseservices,whichmaybewrittenindifferentprogramminglanguages
andusedifferentdatastoragetechnologies.
MartinFowler

20. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 21
@aahoogendoorn
www.ditisagile.nl
Monoliths. Scalability
Product Account
Order Customer
Product Account
Order Customer
Product Account
Order Customer

21. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 22
@aahoogendoorn
www.ditisagile.nl
Microservices. Scalability
Product Account
OrderCustomer

22. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 23
@aahoogendoorn
www.ditisagile.nl
Microservices. Scalability
Product Account
OrderCustomer
Product
CustomerCustomer Customer
Account Account

23. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 24
@aahoogendoorn
www.ditisagile.nl
Microservices. Scalability
Product Account
Order
Product
Customer
Account Account
CustomerCustomer

24. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 25
@aahoogendoorn
www.ditisagile.nl
Monoliths. Persistence
Product Account
Order Customer
Products Accounts
Orders Customers

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©2015 ditisagile.nl. All Rights Reserved 26
@aahoogendoorn
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Microservices. Polyglot persistence
Product Account OrderCustomer
MongoDB
Customers
MongoDB
Orders
ActiveDirectory
Accounts
Oracle
Products

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©2015 ditisagile.nl. All Rights Reserved 27
@aahoogendoorn
www.ditisagile.nl
Microservices. Promises
 Products not projects
 Scalable
 Decentralized governance
 Replaceable parts
 High performance
 Technology independent
 Polyglot persistence
 Easy to build
 Easy to test
 Easier deployment than monoliths
Product
Account
Order
Customer

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©2015 ditisagile.nl. All Rights Reserved 28
@aahoogendoorn
www.ditisagile.nl
Microservices. But…
 What is a microservice exactly?
 How small is a microservice?
 Requirements in a microservice world
 Components or services
 Who owns a microservice?
 What technologies do you use?
 What protocols do you apply?
 How to define messages
 How to test microservices
 How to coordinate when business services run
across components?
 How to build deployment pipelines?
Product
Account
Order
Customer

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©2015 ditisagile.nl. All Rights Reserved 29
@aahoogendoorn
www.ditisagile.nl
Opinions, opinions, opinions

29. @aahoogendoorn
ARE MICROSERVICES
A STAIRWAY TO HEAVEN?

30. @aahoogendoorn
OR A HIGHWAY TO HELL?

31. @aahoogendoorn
MICROSERVICES
IN THE REAL WORLD

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©2015 ditisagile.nl. All Rights Reserved 33
@aahoogendoorn
www.ditisagile.nl
A major Dutch insurance company
We have
 Most functionality on an expensive mainframe
 A wide variety of large systems written in Java that are hard
to maintain and to test, and that are very hard to replace
 Individual systems that cover large areas of functionality,
usually coupled to departments
 Aging technology
 No mobile strategy, allowing for new business or new
services to clients, and intermediaries
We need to
 Get rid of the mainframe
 Shorten time-to-market
 Lower TCO
 Uphold a fully secure systems landscape

33. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 34
@aahoogendoorn
www.ditisagile.nl
FORTHETHINGSWEHAVETOLEARN
BEFOREWECANDOTHEM,
WELEARNBYDOINGTHEM
Aristotle

34. @aahoogendoorn
SO WHAT DID WE LEARN?

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©2015 ditisagile.nl. All Rights Reserved 36
@aahoogendoorn
www.ditisagile.nl
MICROSERVICESREQUIREANEVOLUTIONARYARCHITECTURE

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©2015 ditisagile.nl. All Rights Reserved 37
@aahoogendoorn
www.ditisagile.nl
Questions, questions, questions
Communicationarchitecture.Theglue
Howdowedefineinterfacesbetweenappsandcomponent?Howdowearrangemessaging?
Howdowegluetogetherrapidlychangingappsandcomponent?
Applicationarchitecture
EnduserfacingDifferentusers,differentfastevolvingneeds
Whichtechnologyisthebestforwhichpurpose?
Componentarchitecture
Componentsandservicesareevolvingrapidly.Howdowedecidewhichcomponentsweneed?
Howdowedealwithversioning?Howdowedealwithdistributedprocessesandtransactions?

37. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 38
@aahoogendoorn
www.ditisagile.nl
Our guiding principles
We decided to go from here
 Client thinks in business processes, so we implement
business processes
 We move away from the mainframe, to a new systems
landscape, consisting of micro-applications and micro-
components
 Requirements and documentation are modeled rather than
written
 Applications implement a single (elementary) business
process
 Components serve a single purpose and offer services
 Applications and components all have their own bounded
context – a domain model
 Applications and components will have an similar internal
software architecture to facilitate ease of maintenance and
allow for harvesting re-use
 Communication between applications and components will
use a simple open protocol - REST

38. @aahoogendoorn
APPLICATION ARCHITECTURE

39. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 40
@aahoogendoorn
www.ditisagile.nl
Presentation
Process
Domain
Services
Outsideworld
Pages
Grids/Panels,Controls
Usecases
Flow
Domainobjects,Factories/Repositories
Enums/Valueobjects/Tupels/Referenceobjects
Servicegateways,Serviceclients
Infoobjects/Searchobjects
ComponentsRelations Dossiers Intermediaries Accounts Rates

40. @aahoogendoorn
COMPONENT ARCHITECTURE

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©2015 ditisagile.nl. All Rights Reserved 42
@aahoogendoorn
www.ditisagile.nl
Serviceinterface
Process
Domain
Data/Services
Outsideworld
Resources
Representations
Usecases
Flow
Domainobjects,Factories/Repositories
Enums/Valueobjects/Tupels/Referenceobjects
Storagegateways,Storageclients
Infoobjects/Searchobjects
StorageRelations Dossiers Intermediaries DB2 MongoDB

42. @aahoogendoorn
DESIGNING MICROSERVICES

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©2015 ditisagile.nl. All Rights Reserved 46
@aahoogendoorn
www.ditisagile.nl
DOINGBIGUP-FRONTDESIGNISDUMB
DOINGNODESIGNISEVENDUMBER
DaveThomas

44. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 47
@aahoogendoorn
www.ditisagile.nl
The single unified domain model
Product
Vendor
Stock
Order
Client
Delivery
Payment

45. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 48
@aahoogendoorn
www.ditisagile.nl
Bounded contexts
Product
Vendor
Stock
Order
Client
Delivery
Payment
Product

46. @aahoogendoorn
MODELING APPLICATIONS

47. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 51
@aahoogendoorn
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Smart use cases

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©2015 ditisagile.nl. All Rights Reserved 52
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52
Application
bounded context

49. @aahoogendoorn
MODELING COMPONENTS

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©2015 ditisagile.nl. All Rights Reserved 55
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55Resource
model

51. @aahoogendoorn
AND THE REST IS
COMMUNICATION (OVER HTTP)

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©2015 ditisagile.nl. All Rights Reserved 57
@aahoogendoorn
www.ditisagile.nl
HTTPRETURNCODESCHEATSHEET
1**.Holdon
2**.Hereyougo
3**.Goaway
4**.Youfuckedup
5**.Ifuckedup

53. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 58
@aahoogendoorn
www.ditisagile.nl
HTTP GET
GET
 Retrieve whatever information is
identified by the request URI in the form
of an entity
 The entity is usually a single or a list of
objects (of the type provided by the
service, often JSON, or XML)
 GET is safe (retrieval only) and
idempotent
 Unfortunately there are many ways of
creating GET requests (see examples
below)
 Returns 200 (found), possibly 400 (bad
request) or 404 (not found)
Examples
 Get an entire collection
localhost:8080/countries
 Find objects in the collection
localhost:8080/countries?name=“stan”
 Find an object in the collection by ID
localhost:8080/countries/38
 Find a sub-object in the collection by ID
localhost:8080/countries/38/capital
 Find object in the collection by ISO
localhost:8080/countries?isocode=“GRC”
 Find object in the collection by ISO
localhost:8080/countries/isocode/GRC
 Find object in the collection by ISO
localhost:8080/countries/GRC

54. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 59
@aahoogendoorn
www.ditisagile.nl
BECONSERVATIVEINWHATYOUSEND,
BELIBERALINWHATYOUACCEPT
Postel’sLaw

55. @aahoogendoorn
TESTING MICROSERVICES

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©2015 ditisagile.nl. All Rights Reserved 61
@aahoogendoorn
www.ditisagile.nl
A service development lifecycle
Code DeveloperTest Test IntegrationTest AcceptanceTest LivePrepare&Design

57. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 62
@aahoogendoorn
www.ditisagile.nl
What to test
Code DeveloperTest Test IntegrationTest AcceptanceTest LivePrepare&Design
Developers
Unittests
Developers
Q&A
Testers
Scenario’s&API’s
Testers
Scenario’s&API’s
Productowner
Product

58. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 63
@aahoogendoorn
www.ditisagile.nl
What to test automated
Code DeveloperTest Test IntegrationTest AcceptanceTest LivePrepare&Design
Developers
Unittests
Developers
Q&A
Testers
Scenario’s&API’s
Testers
Scenario’s&API’s
Productowner
Product

59. @aahoogendoorn
DEPLOYING MICROSERVICES
Continuous integration, build pipelines and continuous delivery

60. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 65
@aahoogendoorn
www.ditisagile.nl
A typical build pipeline
Code DeveloperTest Test IntegrationTest AcceptanceTest LivePrepare&Design

61. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 66
@aahoogendoorn
www.ditisagile.nl
ProductionAcceptanceIntegrationTestDevelopment
A typical build pipeline
Code DeveloperTest Test IntegrationTest AcceptanceTest LivePrepare&Design

62. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 67
@aahoogendoorn
www.ditisagile.nl
Build pipelines in Jenkins

63. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 68
@aahoogendoorn
www.ditisagile.nl
Microservices. Building a deployment pipeline
Code DeveloperTest Test AcceptanceTest Acceptance Live
Code DeveloperTest Test AcceptanceTest Acceptance Live
Code DeveloperTest Test AcceptanceTest Acceptance Live
Code DeveloperTest Test AcceptanceTest Acceptance Live

64. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 69
@aahoogendoorn
www.ditisagile.nl
Microservices. Pipeline hell?
Codev.2 DeveloperTestv.2 Testv.2 AcceptanceTestv.2 Acceptancev.2
Code DeveloperTest Test AcceptanceTest Acceptance Live
Testv.2 AcceptanceTestv.2 Acceptancev.2 Livev.2
DeveloperTest Test AcceptanceTest Acceptance Live
Codev.3 DeveloperTestv.3
Live
Codev.2

65. @aahoogendoorn
DO WE REALLY NEED PROJECTS?
From projects to releases to continuous delivery

66. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
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@aahoogendoorn
www.ditisagile.nl
Do we really need projects?

67. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 72
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Or roadmap?

68. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 73
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Minimal viable product

69. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 74
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And go with the flow

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©2015 ditisagile.nl. All Rights Reserved 75
@aahoogendoorn
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Maintenance
From projects to continuous delivery?
Project
MaintenanceMVP
MaintenanceContinuousdelivery

71. @aahoogendoorn

72. @aahoogendoorn
ALLOW YOUR TEAMS TO LEARN
CONTINUOUSLY…

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©2015 ditisagile.nl. All Rights Reserved 79
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The hockey stick model

74. @aahoogendoorn
… AND HAVE FUN

75. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 81
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ONELASTTHOUGHT…

76. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 82
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WHATWILLYOUDOIN2020?

77. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 83
@aahoogendoorn
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You can be anything you want…

78. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
©2015 ditisagile.nl. All Rights Reserved 84
@aahoogendoorn
www.ditisagile.nl
Because…

79. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
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With passion you can achieve amazing things…

80. MICROSERVICES? STAIRWAY TO HEAVEN OR HIGHWAY TO HELL?
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WRITINGCODEISTHEBESTJOBINTHEWORLD

81. @aahoogendoorn
THIS IS
AGILE
www.createspace.com/4747266
Password: agilescrum
Discount code: KGNWKKWG

82. @aahoogendoorn
www.sanderhoogendoorn.com
www.smartusecase.com
www.speedbird9.com
sander@ditisagile.nl
@aahoogendoorn
REFERENCES
AND QUESTIONS