Microservice architecture Microservices vs monolith Design patterns for microservice architecture Further reading

1. Introduction to
Microservices Architecture
Yury KIsliak
ykisliak@eisgroup.com

2. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

3. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

4. Vocabulary
Software architecture

5. Vocabulary
Software architecture
● Components, modules and how they
interact with each other.

6. Vocabulary
● Layers
● Components
● Modules

7. Vocabulary
● Layers
● Components
● Modules

8. Vocabulary
● Layers
● Components
● Modules

9. Vocabulary
● Layers
● Components
● Modules

10. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

11. Kinds of architecture
● Big ball of mud (BBoM)

12. Kinds of architecture
● Service-oriented
architecture (SOA)

13. Kinds of architecture
● Service-oriented
architecture (SOA)

14. Kinds of architecture
● Service-oriented
architecture (SOA)

15. Kinds of architecture
● Service-oriented
architecture (SOA)
○ Monolithic

16. Kinds of architecture
● Service-oriented
architecture (SOA)
○ Monolithic
○ Microservices

17. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

18. Microservices characteristics
● Small
● Independent
● Is built to solve a particular problem domain problem (Bounded Context)
● Interacts with other microservices via network
● Designed for failure
● Development and maintenance require automation

19. Microservices characteristics
● Small
○ Context (not only business, but development as well) can fit in one person's brain
● Independent
○ Contains within it all necessary means to solve a problem (highly cohesive within,
loosely coupled to other microservices)

20. Microservices characteristics
● Is built to solve a particular problem domain problem (Bounded Context)

21. Microservices characteristics
● Interacts with other microservices via network
○ Synchronously or asynchronously
○ Via direct calls or using message-based communications

22. Microservices characteristics
● Designed for failure
○ Other services failure or unavailability is considered as a basic scenario during design
and development and testing (see Chaos monkey)

23. Microservices characteristics
● Development and maintenance require automation
○ Continuous integration and delivery
○ Often requires a dedicated person or a team (DevOps)

24. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

25. Comparison: advantages
Monolith Microservices
Easy to:
- Deploy
- Develop (until certain point)
- Understand and debug (provided
good architecture)
- Do cross module refactoring
Modularity
- Easy and fast changes within
microservice
- Can be developed, tested , released
and delivered independently
- Scalability
Date consistency
- ACID transaction
Availability
- Partial failures tolerance
Development speed (until certain point) Technology Choice

26. Comparison: disadvantages
* Shopify powers 600K merchants and serves 80K requests per second at peak using monolithic architecture
Link.
Monolith Microservices
Scalability is problematic *
Complicated infrastructure components for
- CI
- Monitoring
Degrade with time:
- Huge code base slows down
development (hard to comprehend,
long to compile and run)
- Technical debt can grow
uncontrollably
Need to care a lot about data consistency:
- Message buses
- Complicated patterns lie
Saga, CQRS and Event Sourcing

27. What should you use?
World leading companies use microservices or actively migrating to microservices.

28. What should you use?
Some Melanesian tribes do manufacture airplanes.
https://en.wikipedia.org/wiki/Cargo_cult

29. What should you use?
Monolith Microservices
New unknown domain You have a lot of experience and a couple
of messed up projects behind
Prototypes, PoC Ready to invest in infrastructure and
automation
Create and forget Linear scalability is a must

30. What should you use?
It does not usually necessary to start a project from scratch using microservices.
Microservices is a good way for evolution of applications, which reached limitations of monolithic
architecture. In that case a monolith could be teared apart into microservices gradually: piece by
piece, modules by modules... Or entirely rewritten, if you are bold enough.
When you make a decision to use microservices, you should understand which problems it will
solve and introduce for you. Don’t hope that if you will start doing microservices, then you will
have some benefits just because microservices are cool.
https://www.google.by/search?q=microservices+hell
До микросервисов нужно дорасти, а не начинать с них. (https://habr.com/post/427215/ )
Смерть микросервисного безумия в 2018 году (https://habr.com/company/flant/blog/347518/ )
Микросервисы: пожалуйста, не нужно (https://habr.com/post/311208/ )
Прощайте, микросервисы: от ста проблемных детей до одной суперзвезды (https://habr.com/post/416819/ )

31. What should you use?

32. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

33. Problem: Clients need to call
multiple services to do the to the task.
Pattern: API gateway

34. Problem: Clients need to call
multiple services to do the to the task.
Pattern: API gateway

35. Problem: Clients need to know
where required services is located.
Pattern: Service Discovery

36. Service Discovery: client-sede

37. Service Discovery: server-side

38. Service Discovery: self-registration

39. Service Discovery: registrar

40. Agenda
● Vocabulary
● Kinds of architecture
● Microservices architecture
● Microservices vs monolith
● Design patterns for microservices architecture
● Further reading

41. Further reading
Articles:
Microservices (Martin Fowler)
link
Books:
Building Microservices (Sam Newman, 2016)
link
Domain-Driven Design: Tackling Complexity in the Heart of Software (J. Evans, 2003)
link
Enterprise Integration Patterns (Gregor Hohpe, 2003)
link
Microservices Patterns (Chris Richardson, 2018) + blog microservices.io
link

42. Thank you!
Considering the current sad state of our computer programs, software development is clearly still a black art, and cannot yet be
called an engineering discipline
- Bill Clinton