Case study showing how we decomposed Ctrip mobile backend into microservice architecture for system decoupling, deployability and scalability.

1. MicroService Architecture
@Ctrip
William Yang(杨波)
Dev Manager & Architect
@Ctrip.com

2. Problem Domain
• System decoupling for deployability and
scalability
• Evolutionary architecture and adaptive
organization
• Mobile Backend Architecture

3. Agenda
• The curse of the monolith
• Case study – decomposing Ctrip mobile
backend into microservice
• Microservice best practice
• What we have learned

4. Initial Ctrip Mobile Backend
Architecture
Monolithic Mobile Service
SBU A SBU B SBU C SBU D
SOA/ESB

5. Pros & Cons
• At the beginning …
simple to develop, test, deploy and scale
• Later …
huge, complex, monolithic mobile service

6. The Curse of the Monolith
• Bloated codebase
• Communication and coordination cost
• Obstacle for frequent deployments
• Little resilience to failure
• Commitment to a single technology stack
• Hindering innovation

7. MicroService Architecture Style
• Decomposing a single app as a suite of services
• Communicating with lightweight mechanism
• Built around business capabilities
• Independently deployable
• Minimum of centralized management
• May be written in different programming
languages and use different storages
http://martinfowler.com/articles/microservices.html

8. Who has Migrated to MicroService
http://microservices.io/patterns/microservices.html

9. New Mobile Backend Arch @Ctrip

10. Key MicroService Infrastructure
• Service
– Service framework, gateway, registry
• Monitoring
– Logging, tracing, metrics
• Deployment
– TEST/UAT/PROD environments
– CI/CD
• Push common concerns to technical
infrastructure

11. MicroService Framework @Ctrip

12. Service Metrics Monitoring

13. MicroService Availability
• Assume a monolithic service with 99.99%
availability, what if you have ~30 microservices
each with 99.99% availability??
• Combined effective availability
== 2 HOURS of downtime per month
== 99.7% uptime!!

14. Service Dependency

15. Single Dependency Delay

16. Cascading Failure at Peak Hour

17. Basics of Service Fault Tolerance
• Circuit Breaker(Fuse Blow)
• Isolation
• Rate Limiting
• Fallback

18. Hystrix Circuit Breaker
http://github.com/netflix/hystrix

19. Ctrip Gateway Hystrix Dashboard

20. MicroService Gateway

21. Gateway Filtering Mechanism
“pre” filters “routing” filter(s) “post” filters
Origin Server
“error” filters
HTTP Request
Http Request Http Response
https://github.com/Netflix/zuul

22. Filter Management

23. Advanced Usage of Gateway
• Surgical debugging
• Stress testing
• Canary testing
• Service migration
• Load shedding
• Active/Active traffic management

24. Migration to MicroService
Achievement @Ctrip
• System decoupled and domain ownership
clarified
• Business innovation speed accelerated
• Overall system reliability improved
• Decentralized architecture w/o SPOF
• Develop, test, deploy and scale independently
• Evolutionary architecture

25. What We Have Learned One
• Smooth Migration
– Give buffer to user for migration

26. What We Have Learned Two
• Follow Architecture & Design Best Practice
– Single responsibility & separation of concerns
– Dependency inversion
– Dependency isolation
– Rate limiting & circuit breaker
– Dynamic deployable & re-configurable
• Top-Level Design
– Fit service into infra, not fit infra into service

27. What We Have Learned Three
• Conway’s Law
– “Any organization that design a system(defined
broadly) will produce a design whose structure is a
copy of the organization’s communication
structure” – Melvin Conway, 1968
– “Those system then constrain the options for
organizational change” – Dan North

28. Caveat
• MicroService is not a Free Lunch
– Significant operations overhead
– Substantial DevOps skills required
– Implicit interface
– Duplication of effort
– Distributed system complexity
– Testability challenges
http://highscalability.com/blog/2014/4/8/microservices-not-a-free-lunch.html

29. Future – Soft Load Balancing

30. Future – Cross Data Centers

31. About Me
• William Yang(杨波)
• Dev Manager & Architect @Ctrip Middleware
Team @Shanghai
We are
hiring!

32. 谢谢