Decomposing applications for scalability and deployability - svcc sv_code_camp 2012


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Today, there are several trends that are forcing application architectures to evolve. Users expect a rich, interactive and dynamic user experience on a wide variety of clients including mobile devices. Applications must be highly scalable, highly available and run on cloud environments. Organizations often want to frequently roll out updates, even multiple times a day. Consequently, it’s no longer adequate to develop simple, monolithic web applications that serve up HTML to desktop browsers.
In this talk we describe the limitations of a monolithic architecture. You will learn how to use the scale cube to decompose your application into a set of narrowly focused, independently deployable back-end services and an HTML 5 client. We will also discuss the role of technologies such as NodeJS and AMQP brokers. You will learn how a modern PaaS such as Cloud Foundry simplifies the development and deployment of this style of application.

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Decomposing applications for scalability and deployability - svcc sv_code_camp 2012

  1. 1. Decomposing applications fordeployability and scalability Chris Richardson Author of POJOs in Action Founder of the original @crichardson 1
  2. 2. Presentation goal How decomposing applications improvesdeployability and scalability and How Cloud Foundry helps 2
  3. 3. About Chris 3
  4. 4. (About Chris) 4
  5. 5. About Chris() 5
  6. 6. About Chris 6
  7. 7. About Chris 7
  8. 8. vmc push About-Chris Developer Advocate for CloudFoundry.comSignup at 8
  9. 9. Agenda§The (sometimes evil) monolith§Decomposing applications into services§How do services communicate?§Presentation layer design§How Cloud Foundry helps 9
  10. 10. Let’s imagine you are building an e-commerce application 10
  11. 11. Traditional web application architecture WAR StoreFrontUI Accounting Service MySQL Browser Apache InventoryService Database Shipping ServiceSimple to Tomcat develop test deploy scale 11
  12. 12. But there are problems with a monolithic architecture 12
  13. 13. Users expect a rich, dynamicand interactive experience h oug en ood ’tg HTTP Request isn ure ect Java Web Browser it HTML/Javascript Application Ia rch ty le U s Old Real-time web ≅ NodeJS 13
  14. 14. Intimidates developers 14
  15. 15. Obstacle to frequent deployments§Need to redeploy everything to change one component§Interrupts long running background (e.g. Quartz) jobs§Increases risk of failure Fear of change§Updates will happen less often§e.g. Makes A/B testing UI really difficult 15
  16. 16. Overloads your IDE and container Slows down development 16
  17. 17. Obstacle to scaling development Accounting team E-commerce Engineering application Shipping team 17
  18. 18. Obstacle to scaling development WAR UI team StoreFrontUI Accounting team Accounting Inventory team InventoryService Shipping team Shipping 18
  19. 19. Obstacle to scaling development Lots of coordination and communication required 19
  20. 20. Requires long-term commitment to a technology stack 20
  21. 21. Agenda§The (sometimes evil) monolith§Decomposing applications into services§How do services communicate?§Presentation layer design§How Cloud Foundry helps 21
  22. 22. 22
  23. 23. The scale cubeY axis -functionaldecompositionScale by im ingsplitting g s on r ila tin itidifferent things lit art p gs y ata th ale - d sp i s ax in b Z X axis - horizontal Sc duplication 23
  24. 24. Y-axis scaling - application level WAR StoreFrontUI Accounting Service InventoryService Shipping Service 24
  25. 25. Y-axis scaling - application level accounting web application Accounting Service Store front web application inventory web application InventoryService StoreFrontUI shipping web application Shipping Service Apply X axis cloning and/or Z axis partitioning to each service 25
  26. 26. Partitioning strategies§Partition by verb, e.g. shipping service§Partition by noun, e.g. inventory service§Single Responsibility Principle§Unix utilities - do one focussed thing well Something of an art 26
  27. 27. Real world examples Between 100-150 services are accessed to build a page. eBaySDForum2006-11-29.pdf 27
  28. 28. There are drawbacks 28
  29. 29. Complexity See Steve Yegge’s GooglePlatforms Rant re 29
  30. 30. Multiple databases =Transaction management challenges 30
  31. 31. When to use it? In the beginning: •You don’t need it •It will slow you down Later on: •You need it •Refactoring is painful 31
  32. 32. But there are many benefits§Scales development: develop, deploy and scale each service independently§Update UI independently§Improves fault isolation§Eliminates long-term commitment to a single technology stack Modular, polyglot, multi- framework applications 32
  33. 33. Two levels of architecture System-levelServicesInter-service glue: interfaces and communication mechanismsSlow changing Service-levelInternal architecture of each serviceEach service could use a different technology stackPick the best tool for the jobRapidly evolving 33
  34. 34. If services are small...§Regularly rewrite using a better technology stack§Adapt system to changing requirements and better technology without a total rewrite§Pick the best developers rather than best <pick a language> developers polyglot culture Fred George “Developer Anarchy” 34
  35. 35. The human body as a system 35
  36. 36. 50 to 70 billion of your cells die each day 36
  37. 37. Yet you (the system) remain you 37
  38. 38. Can we build software systems with these characteristics? DesignBeyondHumanAbilitiesSimp.pdf 38
  39. 39. Agenda§The (sometimes evil) monolith§Decomposing applications into services§How do services communicate?§Presentation layer design§How Cloud Foundry helps 39
  40. 40. Inter-service communication options§Synchronous HTTP asynchronous AMQP§Formats: JSON, XML, Protocol Buffers, Thrift, ...§Even via the database Asynchronous is preferred JSON is fashionable but binary format is more efficient 40
  41. 41. Asynchronous message-based communication wgrus-billing.war Accounting Servicewgrus-store.war wgrus-inventory.war RabbitMQ StoreFrontUI (Message InventoryService MySQL Broker) wgrus-shipping.war ShippingService 41
  42. 42. Benefits§Decouples caller from server§Caller unaware of server’s coordinates (URL)§Message broker buffers message when server isdown/slow 42
  43. 43. Drawbacks§Additional complexity of message broker§RPC using messaging is more complex 43
  44. 44. Writing code that calls services 44
  45. 45. The need for parallelism Service B b = serviceB() Call in parallel c = serviceC() Service A Service C d = serviceD(b, c) Service D 45
  46. 46. Java Futures are a greatconcurrency abstraction 46
  47. 47. Akka’s composablefutures are even better 47
  48. 48. Using Akka futuresdef callB() : Future[...] = ...def callC() : Future[...] = ...def callD() : Future[...] = ... Two calls execute in parallelval future = for { (b, c) <- callB() zip callC(); d <- callD(b, c) And then invokes D } yield dval result = Await.result(future, 1 second) Get the result of D 48
  49. 49. Spring Integration§Provides the building blocks for a pipes and filters architecture§Enables development of application components that are •loosely coupled •insulated from messaging infrastructure§Messaging defined declaratively 49
  50. 50. Handling failure Service A Service B Errors happen in distributed systems 50
  51. 51. About Netflix > 1B API calls/day 1 API call average 6 service calls Fault tolerance is essential 51
  52. 52. Use timeouts and retries Never wait forever Errors can be transient retry 52
  53. 53. Use per-dependency bounded thread pool Service A Runnable 1 Task 1 Runnable 2 Task 2 Service B Runnable ... Task ... bounded queue bounded thread pool Fails fast if Limits number ofservice is slow or down outstanding requests 53
  54. 54. Use a circuit breakerHigh error rate stop calling temporarily Down wait for it to come back up Slow gives it a chance to recover 54
  55. 55. On failure Return cached dataAvoidFailing Return default data Fail fast 55
  56. 56. Aspects + Actors Dependency Caller Invoker Implements Aspect circuit breaker state machine CircuitBreakerEquivalent of Actorthread pool Worker Dependency Worker Actor Stub Actor 56
  57. 57. @DependencyProxy trait RestaurantService { def findNearbyRestaurants(location: Location) : Future[FindNearbyRestaurantResponse] } @Service @DependencyProxy(circuitBreaker = "factualCircuitBreaker", timeoutInMilliseconds=750) class FactualRestaurantService extends RestaurantService { ... } 57
  58. 58. Aspect-based Async@Aspectclass DependencyInvokingAspect { @Pointcut("execution(* (@DependencyProxy *).*(..))") def dependencyProxyMethods {} @Around("dependencyProxyMethods()") def invoke(jp: ProceedingJoinPoint) = { val a = AnnotationUtils.findAnnotation(jp.getTarget.getClass, classOf[DependencyProxy]) val actor = findActor(a) val timeout = Timeout(a.timeoutInMilliseconds milliseconds) actor.ask(InvokeDependency( () => jp.proceed())) (timeout) }} Ask actor to invoke jp.proceed() and return Future 58
  59. 59. See for the Actor code 59
  60. 60. Agenda§The (sometimes evil) monolith§Decomposing applications into services§How do services communicate?§Presentation layer design§How Cloud Foundry helps 60
  61. 61. Modular applicationChoice of presentation layer technology 61
  62. 62. NodeJS is the fashionable technology 62
  63. 63. Why NodeJS?§Familiar Javascript§High-performance, scalable event-driven, non-blocking I/O model§Over 13,000 modules developed by the community§Many JavaScript client frameworks have a NodeJS counterpart, e.g. 63
  64. 64. NodeJS example Handle Handle filevar http = require(http); HTTP readvar fs = require("fs"); requesthttp.createServer(function (req, res) { fs.readFile(somefile.txt, function (err, data) { if (err) throw err; res.writeHead(200, {Content-Type: text/plain}); res.end(data); });}).listen(1337,;console.log(Server running at; 64
  65. 65. NodeJS isn’t the only game in town JVM-based 65
  66. 66. A modern web application Service 1 RESTful WS Node JSBrowser HTML 5 Server Application Application Service 2 Events client server ... 66
  67. 67. NodeJS - using RESTful WS and AMQP REST ServiceRESTRequests Node JS Events AMQP AMQP RabbitMQ Service 67
  68. 68. Agenda§The (sometimes evil) monolith§Decomposing applications into services§How do services communicate?§Presentation layer design§How Cloud Foundry helps 68
  69. 69. Original architecture WAR StoreFrontUI Accounting Service MySQLBrowser Apache InventoryService Database Shipping Service Tomcat 69
  70. 70. Modern architecture Desktop Browser Native Mobile application HTML5 mobile application StoreUI StoreUI StoreUIAsynchronous, NodeJS NodeJS Javascript scalable StoreUIcommunication RabbitMQ Spring/Scala web Inventory Shipping Standalone application Inventory Service Shipping Service “headless” Service Service Spring/Java applications MySQL Redis Billing Service Customer Mongo Order Inventory Database Database Database 70
  71. 71. Traditional tools: monolithic applications 71
  72. 72. Developing modular apps is more difficult§Many more moving parts to manage •Platform services: SQL, NoSQL, RabbitMQ •Application services: your code§Who is going to setup the environments: •the developer sandbox? •... •QA environments? But Cloud Foundry helps... 72
  73. 73. Easy polyglot application deployment and service provisioning OSS community vFabricPostgres Ap p lica Private   o Clouds   n  S Data Services erv ice  In ter vFabric fac e RabbitMQTM Public Clouds Msg Services Micro Other Clouds Services Additional partners services …
  74. 74. Creating a platform service instance$ vmc create-service mysql --name mysql1Creating Service: OK$ vmc services......=========== Provisioned Services ============+-------------+---------+| Name | Service |+-------------+---------+| mysql1 | mysql |+-------------+---------+
  75. 75. Multi-application manifest - part 1---applications: inventory/target: Path to application name: inventory url: framework: name: spring info: mem: 512M description: Java SpringSource Spring Application exec: mem: 512M instances: 1 services: Required platform services si-rabbit: type: :rabbitmq si-mongo: type: :mongodb si-redis: type: :redis 75
  76. 76. Multi-application manifest - part 2 store/target: name: store Path to application url: framework: name: spring info: mem: 512M description: Java SpringSource Spring Application exec: mem: 512M instances: 1 services: Required platform services si-mongo: type: :mongodb si-rabbit: type: :rabbitmq 76
  77. 77. One command to create platform services anddeploy application$ vmc pushWould you like to deploy from the current directory? [Yn]:Pushing application inventory...Creating Application: OKCreating Service [si-rabbit]: OKBinding Service [si-rabbit]: OKCreating Service [si-mongo]: OKBinding Service [si-mongo]: OKCreating Service [si-redis]: OKBinding Service [si-redis]: OKUploading Application: Checking for available resources: OK vmc push: Processing resources: OK •Reads the manifest file Packing application: OK Uploading (12K): OK •Creates the required platform servicesPush Status: OKStaging Application inventory: OK •Deploys all the applicationsStarting Application inventory: OKPushing application store...Creating Application: OKBinding Service [si-mongo]: OKBinding Service [si-rabbit]: OKUploading Application: Checking for available resources: OK Processing resources: OK Packing application: OK 77
  78. 78. Micro Cloud Foundry: new developer sandbox App Instances Services Open source Platform as a Service project 10.04 A PaaS packaged as a VMware Virtual Machine Use as a developer sandbox • Use the services from Junit integration tests • Deploy your application for functional testing • Remote debugging from STS 78
  79. 79. Using Caldecott to tunnel into your services 79
  80. 80. Caldecott = TCP over HTTP native native protocol HTTP Service Caldecott Caldecott protocol Service client Port gem application NNNYour computer Cloud Foundry 80
  81. 81. Using Caldecott…$ vmc tunnel1: mysql-135e02: mysql1Which service to tunnel to?: 2Password: ********Stopping Application: OKRedeploying tunnel application caldecott.Uploading Application: Checking for available resources: OK Packing application: OK Uploading (1K): OKPush Status: OKBinding Service [mysql1]: OKStaging Application: OKStarting Application: OKGetting tunnel connection info: OKService connection info: username : uMe6Apgw00AhS password : pKcD76PcZR7GZ name : d7cb8afb52f084f3d9bdc269e7d99ab50Starting tunnel to mysql1 on port 10000.1: none2: mysqlWhich client would you like to start?: 2
  82. 82. …Using CaldecottLaunching mysql --protocol=TCP --host=localhost --port=10000 -- user=uMe6Apgw00AhS --password=pKcD76PcZR7GZ d7cb8afb52f084f3d9bdc269e7d99ab50Welcome to the MySQL monitor. Commands end with ; or g.Your MySQL connection id is 10944342Server version: 5.1.54-rel12.5 Percona Server with XtraDB (GPL), Release 12.5, Revision 188Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type help; or h for help. Type c to clear the current input statement.mysql>
  83. 83. Running JUnit test with Caldecott Configure your test code to use port + connection info 83
  84. 84. Summary 84
  85. 85. Monolithic applications aresimple to develop and deploy BUT have significant drawbacks 85
  86. 86. Apply the scale cube §Modular, polyglot, and scalable applications §Services developed,Y axis -functionaldecomposition ng deployed and scaled independently i on iti rt pa ta da is- ax Z X axis - horizontal duplication 86
  87. 87. Cloud Foundry helps... .js Ap p lica Private   o Clouds   n  S Data Services erv ice  In ter fac e fac e Public ter r  In Clouds Msg Services ide ov  Pr ud Cl o Micro Clouds Other Services
  88. 88. @crichardson crichardson@vmware.com Questions?