Kenny Bastani gave a presentation on moving from monolithic architectures to microservices. He began with an overview of problems with monoliths and how services oriented architectures (SOA) and microservices address these issues. He then provided an example of an online store application broken into microservices. Bastani also discussed how Spring Boot can help develop microservices and the importance of implementing event-driven architectures between distributed services using events, commands, and CQRS. He finished by discussing serverless event handlers and how microservices should leverage events.

1. In the Eventual Consistency of
Succeeding at Microservices
Kenny Bastani
Spring Developer Advocate
GOTO Chicago 2017

2. Kenny Bastani
@kennybastani
Spring Developer Advocate

3. Agenda
Agenda
1 Monolith to Microservices
2 Online store example
3 Spring Boot
4 Event-driven microservices

4. Microservices
How did we get there?

5. We started with the monolith…

6. Slows our velocity getting into
production.
Monolith problems…

7. Engineers take too long to
ramp up.
Monolith problems…

8. The code base becomes too
large for any one person to
reason about.
Monolith problems…

9. Development creates change.
DBAs resist change.
Monolith problems…

10. Coordinated releases batch
many changes together from
different teams.
Monolith problems…

11. Operations drives the runtime
environment of applications.
Monolith problems…

12. Deploy everything at once,
or nothing at all.
Monolith problems…

13. We then moved towards SOA…

14. We have now arrived at microservices…

15. Online Store Example
Cloud native application as microservices

16. @kennybastani

18. Monolith to Microservice

19. Splitting the Monolith: User Service Migration

20. No foreign key constraints
between services.
Microservice problems…

21. I’ve got legacy problems.
Microservice problems…

22. What about my data
warehouse?
Microservice problems…

23. Teams are creating
redundant functionality.
Microservice problems…

24. Distributed transactions are
brittle.
Microservice problems…

25. Every bug is a murder
mystery.
Microservice problems…

26. Distributed systems are
hard.
Microservice problems…

27. Without an event-driven architecture and a
cloud platform…
Microservices will drown you in hard problems
you never knew existed.

28. Spring Boot
A JVM micro-framework for building microservices

29. What is Spring Boot?

30. @kennybastani
spring boot
Spring Initializr for bootstrapping your applications
supports rapid development of
production-ready applications
and services

31. Event-driven microservices
Implementing event-driven architectures in a
distributed system

32. Events as a first-class
citizen.
Event-driven microservices…

33. Domain events have a
subject and contain
immutable data.
Event-driven microservices…

34. Every domain event applies
a state transition to an
aggregate.
Event-driven microservices…

35. Domain events can only be
applied if the aggregate is
in a valid state.
Event-driven microservices…

37. Create meaningful
exceptions if a domain
event cannot be applied.
Event-driven microservices…

38. Event sourcing stores every
state transition as an event
in a log.
Event-driven microservices…

40. Build hypermedia APIs that
attach event logs as a link
on an aggregate.
Event-driven microservices…

41. Commands generate
event(s).
Event-driven microservices…

42. Commands are attached to
aggregates.
Event-driven microservices…

44. Event handlers subscribe to
an event and apply state
changes to an aggregate.
Event-driven microservices…

45. Event handlers use event
sourcing to generate the
current state of an
aggregate.
Event-driven microservices…

47. Event handlers are nodes
on a directed graph.
Event-driven microservices…

49. Events are edges on a
directed graph.
Event-driven microservices…

51. CQRS is used to create
materialized views from
streams of events.
Event-driven microservices…

52. Command Query model

53. @kennybastani

54. @kennybastani

55. @kennybastani

56. @kennybastani

57. Serverless event handlers
Microservices can be event sources

59. Do what makes sense
But don’t build microservices without events

60. $200.00
2 Days, 10 sessions
2 Spring team talks
Live Open Space discussions
Chicago: May 30, 31

61. Thank you!