1. SOA Lessons Learnt
(OR Microservices Done Better)
Sean Farmar
@farmar

2. My journey to SOA
Tried all “Best Practices”
Layers and Tiers
Distributed monoliths using Web Services
… and failed

3. So I went to my
master

4. Solve the problem you want?
mmmm…
Coupling your problem is…

5. Coupling

6. Temporal (time, synchronous calls)
Spatial (deployment, endpoint
address)
Platform (protocols, .Net Remoting)
Coupling
Dimensions

7. Why SOA /
Microservices?
“Address coupling in our software
design by building loosely coupled and
highly encapsulated components”
Udi Dahan

8. Fallacies of
Distributed Computing
1. The network is reliable. (Bill Joy and Tom Lyon)
2. Latency is zero. (Bill Joy and Tom Lyon)
3. Bandwidth is infinite. (Bill Joy and Tom Lyon)
4. The network is secure. (Bill Joy and Tom Lyon)
5. Topology doesn’t change. (Peter Deutsch)
6. There is one administrator. (Peter Deutsch)
7. Transport cost is zero. (Peter Deutsch)
8. The network is homogeneous. (James Gosling)

9. The Fallacies EBook
• Go to: http://go.particular.net/KGD16

10. Encapsulation
Autonomy
Decomposing Business entities
SRP
Keep your vertical slice thin, top to bottom

11. Monolith
UI
BL
DAL
DB
Tight Coupling
Loose Coupling

12. Vertical Slicing
UI
BL
DAL
DB Referential Integrity
Tight Coupling
Loose Coupling
Re-introduces Coupling
Sales
Conten
t
CRMOps

13. Lessons learnt
It’s hard (er)
Decomposing your business domain, is hard,
avoid the pitfalls of standard design
methodologies
Messaging: Fire and forget
CQS: Separating data writes and data reads
Data (write) ownership
Referential integrity and GUIDS

14. Lessons learnt(cont.)
DATA: separate OLTP and reporting,
eventual consistency
Monitoring - Lights on
Testing is HARD
Deployment - Automate everything
Organization and people, trust

15. Summary
• Avoid all dimensions of coupling
• No synchronous communication between
components/microservices,
• Don't share data, use view/read models to share read only
data
• Decomposing your business domain and entities
• You can do it on .Net platform using NServiceBus
• Blog post: http://particular.net/blog/goodbye-
microservices-hello-right-sized-services
• Fallacies EBook: http://go.particular.net/KGD16

16. Q&A
Thank You!
Sean Farmar
twitter: @farmar
Particular.net