•專屬伺服器、分流設計 Netflix解決全球驚人流量之道 https://www.cool3c.com/article/104032 •Pattern: Microservice Architecture https://microservices.io/patterns/microservices.html •What’s a service - part 1? http://chrisrichardson.net/post/microservices/general/2019/02/16/whats-aservice-part-1.html •Pattern: Saga https://microservices.io/patterns/data/saga.html •The Scale Cube https://microservices.io/articles/scalecube.html •技術棧：它的定義以及構建方式 https://mixpanel.com/zh-hant/topics/what-is-a-technology-stack/?msclkid=c2b64b17c5da11ecb1084e6a3f038b9b 技術棧也稱解決方案棧、技術基礎結構或數據生態系統，是用於構建和執行某款應用程式的所有技術服務的清單。 •[Domain Driven Design] 簡介和為什麼你需要DDD https://medium.com/%E7%A7%91%E6%8A%80%E6%96%B0%E6%83%B3/domain-driven-design- %E7%B0%A1%E4%BB%8B%E5%92%8C%E7%82%BA%E4%BB%80%E9%BA%BC%E4%BD%A0%E9%9C%80%E8%A6%81ddd6cf4ceed6088 •Documenting a service using the microservice canvas https://chrisrichardson.net/post/microservices/general/2019/02/27/microservice-canvas.html

1. Microservice 微服務
Presenter：CHEN,YOU-SHENG (Shane)
111/04/29 Fri

2. CONTENTS
1. Known uses
2. Key characteristics of a service
3. The structure of a service
4. Benefits and drawbacks
5. Microservice canvas
6. Forces of a service
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2

3. Known uses
A very popular video streaming service
Responsible for up to 30% of Internet traffic
A large scale, service-oriented architecture
Handle over a billion calls per day to their video
streaming API from over 800 different kinds of
devices
Each API call fans out to an average of six calls to
backend services
相片(標題) CC BY-SA 授權
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1
Netflix proprietary server
(Source by broadband analytics firm Sandvine)

4. Known uses
A multinational technology company
Migrated to a service-oriented architecture
consisting of hundreds of backend services
Website application calls 100-150 services to
get the data that used to build a web page
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4
2
Amazon S3 data center
相片(標題) CC BY
(Source by Amazon Architecture http://highscalability.com/amazon-architecture )

5. Known uses
A multinational e-commerce corporation
The application tier consists of multiple
independent applications
 Each application uses X-axis splits and
some applications such as search use Z-
axis splits
 Also applies a combination of X-, Y- and
Z-style scaling to the database tier
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5
3
相片 (標題) CC BY-SA 授權

6. Key characteristics of a service
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6
Highly maintainable
and testable
• rapid and frequent
development and
deployment
Loosely coupled
with other services
• without being
impacted by changes
to other services
• without affecting
other services
Independently
deployable
• enables a team to
deploy their service
without having to
coordinate with other
teams
Capable of being
developed by a
small team
• avoiding the high
communication
overhead of large
teams

7. The structure of a service
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7
The core of the service is its business logic, which is surrounded by adapters that communicate with
other services and applications
Operations
A command is an operation
that mutates data;
A query is a command that
retrieves data
Events
A service publishes events
to a message channel
implemented by a message
broker
• operations of other
services
• subscribes to their events
• persists data in the
service’s database

8. The structure of a service -Example
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8
• Let’s imagine that you are building an
e-commerce application
• Services communicate using either
synchronous protocols such as
HTTP/REST or asynchronous protocols
such as AMQP
• Each service has its own database
• Data consistency between services is
maintained using the Saga pattern
Fictitious e-commerce application(checking credit, maintaining inventory
and shipping orders)

9. The structure of a service -Saga pattern
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9
 A saga is a sequence of local transactions
 Each local transaction updates the database and publishes a message or event to
trigger the next local transaction in the saga
 If a local transaction fails then the saga undo the changes that were made by the
preceding local transactions

10. Benefits and drawbacks
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10
Enables the continuous delivery and deployment
• Improved maintainability (easier to change)
• Better testability (faster to test)
• Deployed independently
• Each team can develop, test, deploy and scale their services independently of all of the other teams
Each microservice is relatively small
• Making developers more productive (easier to understand)
• The application starts faster
Improved fault isolation
• Other services will continue to handle requests(if fault)
Eliminates any long-term commitment to a technology stack

11. Benefits and drawbacks
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11
Additional complexity of creating a distributed system
• Implement the inter-service communication mechanism and deal with partial failure
• Cross-multiple services is more difficult
• Testing the interactions is difficult
• Careful coordination between the teams
Deployment complexity
• Complexity of deploying and managing a system comprised of many different
services
Increased memory consumption

12. Microservice canvas
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12
External view
• Name：name of the service Name
• Description：a brief description of the service Description
• Capabilities：the business capabilities implemented by the service
• Service API：the operations implemented by the service and the
domain events published by the service
• Quality attributes：non-functional attributes
• Observability：includes health check endpoint, key metrics
Implementation
• DDD(domain-driven design) subdomain 、Use Case、Resources
Dependencies
• Invokes：the operations, which are implemented by other
services that this service invokes invoke
• Subscribes to：the messages, which includes events, that this
service subscribes to
Examples of the microservice canvas https://github.com/cer/microservice-canvas
(Matt McLarty and Irakli Nadareishvili, 2017)
Domain-Driven Design: Tackling Complexity in the Heart of Software

13. Forces of a service
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13
 New team members must quickly become productive
 The application must be easy to understand and modify
 To practice continuous deployment of the application
 Must run multiple instances of the application on multiple
machines in order to satisfy scalability and availability
requirements
 To take advantage of emerging technologies
(frameworks, programming languages and etc)

14. Thank you

15. •專屬伺服器、分流設計 Netflix解決全球驚人流量之道 https://www.cool3c.com/article/104032
•Pattern: Microservice Architecture https://microservices.io/patterns/microservices.html
•What’s a service - part 1? http://chrisrichardson.net/post/microservices/general/2019/02/16/whats-a-service-part-
1.html
•Pattern: Saga https://microservices.io/patterns/data/saga.html
•Node之可擴展性 --- Node的Cluster
https://mark-lin.com/posts/20170605/?msclkid=94b976b0c76011ecb073e53267a36d3c
•The Scale Cube https://microservices.io/articles/scalecube.html
 x: 負載平衡
If there are N copies then each copy handles 1/N of the load
 Y: Y-axis axis scaling splits the application into multiple
Each service is responsible for one or more closely related functions
(using noun / verb to split service )
Resources

16. •技術棧：它的定義以及構建方式 https://mixpanel.com/zh-hant/topics/what-is-a-technology-
stack/?msclkid=c2b64b17c5da11ecb1084e6a3f038b9b
技術棧也稱解決方案棧、技術基礎結構或數據生態系統，是用於構建和執行某款應用程式的所有技術服務的清單。
•[Domain Driven Design] 簡介和為什麼你需要DDD
https://medium.com/%E7%A7%91%E6%8A%80%E6%96%B0%E6%83%B3/domain-driven-design-
%E7%B0%A1%E4%BB%8B%E5%92%8C%E7%82%BA%E4%BB%80%E9%BA%BC%E4%BD%A0%E9%9C%80%E8%A6%81ddd-
6cf4ceed6088
•Documenting a service using the microservice canvas
https://chrisrichardson.net/post/microservices/general/2019/02/27/microservice-canvas.html
•P13 Microsoft Stock images (royalty-free images)
•PPT template- IT PowerPoint Template https://prezentr.com/templates/it-powerpoint-template/
Resources