By using AWS Lambda, we get to know more about Serverless computing.

1. 淺談
SERVERLESS
Focusing on AWS Lambda

2. No server is easier to
manage than no server.
Werner Vogels

3. http://martinfowler.com/articles/serverless.html

4. https://youtu.be/U8ODkSCJpJU?t=240
AWS Lambda

5. 什麼是 Serverless ? 什麼是 Lambda ?
▸Serverless can also mean applications where some amount
of server-side logic is still written by the application
developer but unlike traditional architectures is run in
stateless compute containers that are event-triggered,
ephemeral (may only last for one invocation)
▸AWS Lambda is a compute service that lets you run code
without provisioning or managing servers
http://martinfowler.com/articles/serverless.html

6. 现在的微服务架构是
container 级别的。lambda把
这个粒度做到function级别了
阳衡锋
文字
https://www.zhihu.com/question/29490143

10. Event handler 內的兩個參數
▸Event
▸Trigger lambda 的 event 來源
▸s3, sns, API gateway, DynamoDB…etc.
▸Context
▸跟 Lambda service 溝通可拿到的 runtime information
▸AWS 停掉 function 前剩餘的時間
▸Cloudwatch log group and log stream
▸觸發 function 執行的 requestID (可用來查詢 Support)
▸AWS mobile SDK 可以拿到 mobile 的資訊

11. DEMO
01-HelloWorld-Lambda

12. 文字
Lambda 的限制 1/3
▸必須設計成 stateless
▸有最大memory限制
▸有最大執行時間限制

13. 文字
Lambda 的限制 2/3

14. 文字
Lambda 的限制 3/3

15. Lambda 到底是怎麼搞的？
▸每個 function 在獨立 container sandbox 中執行，resource,
configuration 與其他 function 分開
▸Lambda Container Reuse (freeze-thaw cycle)
▸Lambda Host 在運行 Function 時，會重覆利用 Container
；Container 若正常結束，Lambda 會保存當下狀態
(freeze) 備日後復用
▸Function 再次執行時，若該 Frozen Container 仍然可用，
Lambda 會重新啟動 (thaw) 並執行 handler，無需再初始化
https://aws.amazon.com/tw/blogs/compute/container-reuse-in-lambda/

16. Lambda 到底是怎麼搞的？
▸對岸神人自幹 Lambda
▸Lambda Docker
▸Docker + Swarm
▸event-driven code runtime like AWS Lambda service
▸https://github.com/tobegit3hub/lambda-docker

17. Retries on Errors
▸Lambda fail 的三種原因
▸Times out
▸Fails to parse input data
▸Reaches resource constraints: memory, other timeout
▸Retry
▸Non-stream-based event source
▸SYNC: invoking application receive 429 error
▸ASYNC: DLQ (Dead Letter Queue) 沒設定 event 會被 discard
▸Stream-based even source
▸Kinesis, DynamoDB
▸lambda 會持續 retry 拉資料直到 data expired，為了確保 order 會是 blocking 狀態
(不會繼續讀新資料直到 failed batch 成功做完或 expired)

18. Avoid Chaos
▸Lambda version control
▸stage variable
▸良好且固定的 naming rule
▸加上 prefix，參考
arn 命名規則
▸使用 deployment tool
▸aws cli
▸cloudformation
▸serverless framework: serverless, Apex…etc
▸Orchestration生態尚未成熟，需暫時自己手刻
API Gateway Lambda FQDN
/prod/Resources auth:stable https://api.diamond
/dev/Resources auth:$LATEST
https://api-
dev.diamond
/qa/Resources auth:qa
https://api-
qa.diamond

19. DEMO
02-HelloWorld-APIGW-Lambda

20. JAWS Serverless

21. 各種 Use case
▸使用者註冊 : API GW + Lambda + DynamoDB + SES
▸使用者認證 : API GW + Lambda + Cognito/IAM
▸RESTful API : API GW + Lambda
▸各種 event-driven 使用 lambda
▸Static website hosting : Cloudfront + S3 + Lambda
▸Log parsing/monitoring : Cloudwatch + Lambda
▸Data Analyzing : Kinesis + Lambda

22. DEMO
03-Rate-Based blacklisting with
AWS WAF and Lambda

23. SCENARIO
Without AWS WAF
Web server
User
Attacker

24. SCENARIO
With AWS WAF
Web server
User
Attacker

26. Block request

27. Pros & Cons
▸Cost could be reduced
▸Demand based 的計價方式更適合 bursty traffic 類型
▸Scale 更容易
▸更容易 maintain 每個 component
▸Cost could be increased
▸在 design 的時候就必須有拆分小 service 的 overhead
▸Local development and unit testing 不容易
▸realtime end-to-end testing
▸docker-lambda (很像 AWS lambda 環境的 docker image, test runners)

28. 文字
以 Nebula 舉個例子
▸可以將 task 拆分為兩大類
▸event-driven: security event, user-triggered event, scan result
reporting…etc.
▸periodical event: profile pulling, HW health reporting, daily scan
reporting…etc.
▸拆開以後 (decoupled)
▸easier to deploy
▸easier to try new things
▸降低 long-run EC2 instance 的規格

29. ONE
MORE
THING

30. AWS STEP FUNCTIONS