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Decomposing applications for deployability and scalability (CF India July/August 2012)

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Latest version of the decomposing applications for scalability and deployability talk. From Cloud Foundry July/August India tour.

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Decomposing applications for deployability and scalability (CF India July/August 2012)

  1. 1. Decomposing applications fordeployability and scalability Chris Richardson Author of POJOs in Action Founder of the original CloudFoundry.com @crichardson crichardson@vmware.com http://plainoldobjects.com/ 1
  2. 2. Presentation goal How decomposing applications improves deployability and scalability and How Cloud Foundry helps 2
  3. 3. About Chris 3
  4. 4. dsply ‘About Chris’; RPG 4
  5. 5. (About Chris) 5
  6. 6. About Chris() 6
  7. 7. About Chris 7
  8. 8. About Chris http://www.theregister.co.uk/2009/08/19/springsource_cloud_foundry/ 8
  9. 9. vmc push About-Chris Developer Advocate for CloudFoundry.comSignup at http://cloudfoundry.com 9
  10. 10. Agenda The (sometimes evil) monolith Decomposing applications into services How do services communicate? Presentation layer design How Cloud Foundry helps 10
  11. 11. Let’s imagine you are building an e- commerce application 11
  12. 12. Traditional web application architecture WAR StoreFrontUI Accounting Service MySQL Browser Apache InventoryService Database Shipping ServiceSimple to Tomcat develop test deploy scale 12
  13. 13. But there are problems 13
  14. 14. Users expect a rich, dynamic andinteractive experience on mobiledevices and desktop h oug d en oo ’t g HTTP Request e isn r ctu Java Web Browser e hit HTML/Javascript Application c I ar ty le U s Old Real-time web ≅ NodeJS 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 WAR StoreFrontUI Accounting Scalable != InventoryService development Shipping Forces teams to synchronize development efforts Teams need to coordinate updates 17
  18. 18. Requires long-term commitment to a technology stack Switching technology stack touches entire application Painful and rarely done Makes it difficult to incrementally adopt newer technologies You end up being stuck with the technology you started with 18
  19. 19. Agenda The (sometimes evil) monolith Decomposing applications into services How do services communicate? Presentation layer design How Cloud Foundry helps 19
  20. 20. 3 dimensions to scalingY axis -functionaldecompositionScale by s ngsplitting ila g n hi g s oni rtdifferent things iti rt im pa ta in da ittl s- sp i ax by Z ale X axis - horizontal duplication Sc Scale by cloning 20
  21. 21. Y axis scaling - functional partitioning Splits monolithic application into a set of services Each service implements a set of related functionality Partitioning schemes: • Partition functionality by noun or by verb • Single Responsibility Principle • Unix utilities - do one focussed thing well Something of an art 21
  22. 22. Y axis scaling - application level WAR StoreFrontUI Accounting Service InventoryService Shipping Service 22
  23. 23. Y axis scaling - application level billing web application Accounting Service Store front web application inventory web application StoreFrontUI InventoryService shipping web application Shipping Service Apply X axis cloning and/or Z axis partitioning to each service 23
  24. 24. Real world examples http://techblog.netflix.com/ Between 100-150 services are accessed to build a page. http://highscalability.com/amazon-architecture http://www.addsimplicity.com/downloads/ eBaySDForum2006-11-29.pdf http://queue.acm.org/detail.cfm?id=1394128 24
  25. 25. There are drawbacks Complexity: development, deployment, etc. Multiple databases transaction management challenges Deciding when to use it • In the beginning: you don’t need it and it will slow you down • When you do need it: refactoring existing code is painful See Steve Yegge’s Google Platforms Rant re Amazon.com 25
  26. 26. But there are many benefits Scales development: develop, deploy and scale each service independently Improves fault isolation Enforces well defined interfaces between components Eliminates long-term commitment to a single technology stack Modular, polyglot, multi- framework applications 26
  27. 27. Two levels of architecture System level • Defines the inter-service glue: interfaces and communication mechanisms • Slow changing Versus Service level • Defines the internal architecture of each service • Far fewer constraints on technology • Each service could use a different technology stack • Pick the best tool for the job • Rapid evolving 27
  28. 28. 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” 28
  29. 29. The human body as a system 29
  30. 30. 50 to 70 billion of your cells die each day 30
  31. 31. Yet you (the system) remain you 31
  32. 32. Can we build software systems with these characteristics? http://dreamsongs.com/Files/ DesignBeyondHumanAbilitiesSimp.pdf http://dreamsongs.com/Files/WhitherSoftware.pdf 32
  33. 33. Agenda The (sometimes evil) monolith Decomposing applications into services How do services communicate? Presentation layer design How Cloud Foundry helps 33
  34. 34. Inter-service communication options Multiple collaborating services need a communication mechanism Many choices: • Synchronous asynchronous • Transports: HTTP, AMQP, ... • Formats: JSON, XML, Protocol Buffers, Thrift, ... • Even via the database Distributed application error handling strategies Asynchronous is preferred JSON is fashionable but binary format is more efficient 34
  35. 35. Asynchronous message-based communication wgrus-billing.war Accounting Servicewgrus-store.war wgrus-inventory.war RabbitMQ StoreFrontUI (Message InventoryService MySQL Broker) wgrus-shipping.war ShippingService 35
  36. 36. Benefits and drawbacks Benefits • Decouples caller from server • Caller unaware of server’s coordinates (URL) • Message broker buffers message when server is down/slow Drawbacks • Additional complexity of message broker • RPC using messaging is more complex 36
  37. 37. Writing code that calls services 37
  38. 38. Composable futures Problem: • Service A needs to call services B and C and then D • Makes sense to call B and C parallel • Yet most concurrency APIs are low-level, error-prone etc Solution: • Use Akka composable futures = really nice abstraction val futureB = callB() Two calls execute in parallel val futureC = callC() val futureD = for { b <- futureB.mapTo[SomeType] c <- futureC.mapTo[SomeType] d <- callD(b, c) And then invokes D } yield d val result = Await.result(futureD, 1 second). asInstanceOf[SomeOtherType] Get the result of D http://doc.akka.io/docs/akka/2.0.1/scala/futures.html http://en.wikipedia.org/wiki/Futures_and_promises 38
  39. 39. Spring Integration Builds on Spring framework Implements EAI patterns = high-level of abstraction for building message based applications Provides the building blocks for a pipes and filters architecture • Pipes = message channels • Filters = endpoints that filter, transform, route messages and integrate with external messaging infrastructure Enables development of components that are • loosely coupled • insulated from underlying messaging infrastructure 39
  40. 40. Handling failure Service A Service B Errors happen in distributed systems 40
  41. 41. Use timeouts and retries Never wait forever Errors can be transient retry http://techblog.netflix.com/2012/02/fault-tolerance-in-high-volume.html 41
  42. 42. 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 42 http://techblog.netflix.com/2012/02/fault-tolerance-in-high-volume.html
  43. 43. Use a circuit breaker High error rate stop calling temporarily Avoids calling service that has issues Down wait for it to come back up Slow gives it a chance to recover http://techblog.netflix.com/2012/02/fault-tolerance-in-high-volume.html 43
  44. 44. On failure - don’t fail too Return cached data Return default data Invoke custom error handler http://techblog.netflix.com/2012/02/fault-tolerance-in-high-volume.html 44
  45. 45. Agenda The (sometimes evil) monolith Decomposing applications into services How do services communicate? Presentation layer design How Cloud Foundry helps 45
  46. 46. Modular applicationChoice of presentation layer technology + Redeploy UI frequently/independently 46
  47. 47. NodeJS is the fashionable technologyMany JavaScript client frameworks have a NodeJS counterparte.g. socket.io 47
  48. 48. NodeJS example Handle HTTP Handle file request var http = require(http); read var fs = require("fs"); http.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; 48
  49. 49. NodeJS isn’t the only game in town JVM-based http://vertx.io/ 49
  50. 50. A modern web application Service 1 RESTful WS Node JSBrowser HTML 5 Server Application Application Service 2 Events Socket.io Socket.io client server ... 50
  51. 51. NodeJS - using RESTful WS and AMQP REST ServiceRESTRequests Node JS Events socket.io AMQP AMQP RabbitMQ Service 51
  52. 52. Updating the UI is easy Update the UI independently of rest of system Easily run A/B tests Enables fast iteration of the UI http://theleanstartup.com/principles 52
  53. 53. Agenda The (sometimes evil) monolith Decomposing applications into services How do services communicate? Presentation layer design How Cloud Foundry helps 53
  54. 54. Traditional tools: monolithic applications 54
  55. 55. 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... 55
  56. 56. Easy polyglot application deployment and service provisioning OSS community vFabricPostgres Ap p lica Data Private   o Services Clouds   n  S erv ice  In vFabric ter fac RabbitMQTM Msg Public e Services Clouds Micro Other Clouds Services Additional partners services …
  57. 57. Creating a platform service instance$ vmc create-service mysql --name mysql1Creating Service: OK$ vmc services......=========== Provisioned Services ============+-------------+---------+| Name | Service |+-------------+---------+| mysql1 | mysql |+-------------+---------+
  58. 58. Multi-application manifest - part 1 --- applications: inventory/target: Path to application name: inventory url: cer-inventory.chrisr.cloudfoundry.me 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 58
  59. 59. Multi-application manifest - part 2 store/target: Path to application name: store url: cer-store.chrisr.cloudfoundry.me 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 59
  60. 60. One command to create platform services and deployapplication $ vmc push Would you like to deploy from the current directory? [Yn]: Pushing application inventory... Creating Application: OK Creating Service [si-rabbit]: OK Binding Service [si-rabbit]: OK Creating Service [si-mongo]: OK Binding Service [si-mongo]: OK Creating Service [si-redis]: OK Binding Service [si-redis]: OK Uploading Application: Checking for available resources: OK Processing resources: OK Packing application: OK vmc push: Uploading (12K): OK Push Status: OK •Reads the manifest file Staging Application inventory: OK Starting Application inventory: OK •Creates the required platform services Pushing application store... Creating Application: OK •Deploys all the applications Binding Service [si-mongo]: OK Binding Service [si-rabbit]: OK Uploading Application: Checking for available resources: OK Processing resources: OK Packing application: OK Uploading (5K): OK Push Status: OK Staging Application store: OK 60 Starting Application store: ...
  61. 61. 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 61
  62. 62. Using Caldecott to tunnel into your services 62
  63. 63. Caldecott = TCP over HTTP native native protocol HTTPService Caldecott Caldecott protocol Service client Port gem application NNNYour computer Cloud Foundry 63
  64. 64. 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
  65. 65. …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>
  66. 66. Running JUnit test with Caldecott Configure your test code to use port + connection info 66
  67. 67. Summary Monolithic applications are simple to develop and deploy BUT have significant drawbacks Applying the scale cube Decomposes your application into services Enables scaling for transactions and data volumes Tackles application complexity Enables scaling for development Enables frequent, independent deployments Make it easy to leverage other technologies AND Cloud Foundry simplifies the development and deployment of modular, service-based applications 67
  68. 68. @crichardson crichardson@vmware.comhttp://slideshare.net/chris.e.richardson/ Questions? www.cloudfoundry.com