Akka 2.0: Scaling Up & Out With Actors

Viktor Klang, tech lead of Akka at Typesafe, discusses scaling software with actors at the 2012 North East Scala Symposium. Traditional approaches to concurrency and distribution force the issue of choosing between productivity and scalability. The cause of that has been the wrong tools and the wrong layer of abstraction and Akka is here to change that.

Akka is a unified runtime and programming model for scaling both UP (utilizing multi-core processors) and OUT (utilizing the grid/cloud). With Akka 2.0 this will be taken to a whole new level, "Distributed by Design".

Transcript

1. Scaling up & out - with Actors √ Akka Tech Lead Email: viktor.klang@typesafe.com Twitter: @viktorklang Saturday, March 10, 12
2. 2.0 Saturday, March 10, 12
3. Akka (Áhkká): The name comes from the goddess in the Sami mythology that represented all the wisdom and beauty in the world. It is also the name of a beautiful mountain in Laponia in the north part of Sweden 2.0 Saturday, March 10, 12
4. View from the summit 2.0 Saturday, March 10, 12
5. The problem It is way too hard to build ‣ correct highly concurrent systems ‣ truly scalable systems ‣ self-healing, fault-tolerant systems ...using “state-of-the-art” tools Saturday, March 10, 12
6. Concurrency Scalability Fault-tolerance …made Simpler Vision Saturday, March 10, 12
7. Manage system overload Saturday, March 10, 12
8. Scaling: up & out Saturday, March 10, 12
9. Replicate and distribute for fault-tolerance Saturday, March 10, 12
10. Transparent load balancing Saturday, March 10, 12
11. Markets Use cases FINANCE & BANKING BETTING & GAMING TELECOM & TV E-COMMERCE SIMULATION SOCIAL • Event-driven messaging systems • Stock trend Analysis & Simulation • Streaming media network gateways • Massive multiplayer online gaming • High throughput and transactional betting • 3D simulation engines • Social media community sites Applicability Saturday, March 10, 12
12. Akka 2.0 Saturday, March 10, 12
13. Design for distribution – In-VM is an optimization opportunity Saturday, March 10, 12
14. Async at heart – Even for control Saturday, March 10, 12
15. CAS is mother, CAS is father. – No locks in hot path Saturday, March 10, 12
16. Fault-tolerance as default – Enforced parental supervision Saturday, March 10, 12
17. Always room for improvement – Simplify, Refactor, Replace Saturday, March 10, 12
18. A simple version bump? Saturday, March 10, 12
19. 700 tickets closed Saturday, March 10, 12
20. 1020 files changed Saturday, March 10, 12
21. 98683 lines added Saturday, March 10, 12
22. 57415 lines removed Saturday, March 10, 12
23. Scale up Saturday, March 10, 12
24. Akka Actors one tool in the toolbox Saturday, March 10, 12
25. Behavior State Actor Saturday, March 10, 12
26. Event- driven Behavior State Actor Saturday, March 10, 12
27. Event- driven Behavior State Actor Saturday, March 10, 12
28. Event- driven Behavior State Actor Saturday, March 10, 12
29. Event- driven Behavior State Actor Saturday, March 10, 12
30. Event- driven Behavior State Actor Saturday, March 10, 12
31. Behavior State Actor Saturday, March 10, 12
32. Event- driven Behavior State Actor Saturday, March 10, 12
33. import akka.actor.ActorSystem import com.typesafe.config.ConfigFactory val system = ActorSystem( “my-app-name”, ConfigFactory.load(“application”) ) Create Application Scala API Saturday, March 10, 12
34. case object Tick class Counter extends Actor { var counter = 0 def receive = { case Tick => counter += 1 println(counter) } } Actors Scala API Saturday, March 10, 12
35. val counter = system.actorOf(Props[Counter]) Create Actors counter is an ActorRef Creates a top-level actor Scala API Saturday, March 10, 12
36. system stop actorRef Stop actors ...also stops all actors in the hierarchy below Saturday, March 10, 12
37. counter ! Tick Send: ! Scala API fire-forget Saturday, March 10, 12
38. counter tell Tick counter.tell(Tick, sender) ...or use tell fire-forget Scala API Saturday, March 10, 12
39. import akka.patterns.ask implicit val timeout = Timeout(5 seconds) val f = actor ? message Send: ? returns a Future[Any] Scala API Saturday, March 10, 12
40. import akka.patterns.ask val future = ask(actor, message, 5 seconds) Send: ? returns a Future[Any] Scala API Saturday, March 10, 12
41. class SomeActor extends Actor { def receive = { case User(name) => // reply to sender sender ! (“Hi ” + name) } } Reply Scala API Saturday, March 10, 12
42. become context become { // new body case NewMessage => ... } Scala API Saturday, March 10, 12
43. unbecome context.unbecome() Saturday, March 10, 12
44. Routers ‣ RoundRobin ‣ Random ‣ SmallestMailbox ‣ Broadcast ‣ ScatterGatherFirstCompleted … Custom Saturday, March 10, 12
45. Routers val router = system.actorOf( Props[SomeActor].withRouter( RoundRobinRouter(nrOfInstances = 5))) Scala API Saturday, March 10, 12
46. Router + Resizer val resizer = DefaultResizer(lowerBound = 2, upperBound = 15) val router = system.actorOf( Props[ExampleActor1].withRouter( RoundRobinRouter(resizer = Some(resizer)) ) ) Scala API Saturday, March 10, 12
47. Scale up? Saturday, March 10, 12
48. ThreadPoolExecutor Saturday, March 10, 12
49. ThreadPoolExecutor Saturday, March 10, 12
50. new ForkJoinPool Saturday, March 10, 12
51. new ForkJoinPool Saturday, March 10, 12
52. ~2.7m actors/GB Saturday, March 10, 12
53. Let it crash fault-tolerance Saturday, March 10, 12
54. Saturday, March 10, 12
55. Which components have critically important state and explicit error handling? Saturday, March 10, 12
56. Saturday, March 10, 12
57. Fault-tolerant onion-layered Error Kernel Saturday, March 10, 12
58. Error Kernel Saturday, March 10, 12
59. Error Kernel Saturday, March 10, 12
60. Error Kernel Saturday, March 10, 12
61. Error Kernel Saturday, March 10, 12
62. Error Kernel Saturday, March 10, 12
63. // from within an actor val child = context.actorOf(Props[MyActor], “my-actor”) Parental automatic supervision Scala API transparent and automatic fault handling by design Saturday, March 10, 12
64. Guardian System Actor Parental automatic supervision Saturday, March 10, 12
65. Guardian System Actor Parental automatic supervision system.actorOf(Props[Foo], “Foo”) Saturday, March 10, 12
66. Foo Guardian System Actor Parental automatic supervision system.actorOf(Props[Foo], “Foo”) Saturday, March 10, 12
67. Foo Guardian System Actor Parental automatic supervision context.actorOf(Props[A], “A”) Saturday, March 10, 12
68. A Foo Guardian System Actor Parental automatic supervision context.actorOf(Props[A], “A”) Saturday, March 10, 12
69. A B Bar Foo C B E A D C Guardian System Actor Parental automatic supervision Saturday, March 10, 12
70. A B Bar Foo C B E A D C Name resolution Guardian System Actor Saturday, March 10, 12
71. A B Bar Foo C B E A D C /Foo Name resolution Guardian System Actor Saturday, March 10, 12
72. A B Bar Foo C B E A D C /Foo /Foo/A Name resolution Guardian System Actor Saturday, March 10, 12
73. A B Bar Foo C B E A D C /Foo /Foo/A /Foo/A/B Name resolution Guardian System Actor Saturday, March 10, 12
74. A B Bar Foo C B E A D C /Foo /Foo/A /Foo/A/B Name resolution /Foo/A/D Guardian System Actor Saturday, March 10, 12
75. ActorPath val actorRef = system.actorFor("/user/pigdog") val parent = context.actorFor("..") val sibling = context.actorFor("../pigdog") val refPath: ActorPath = actorRef.path Saturday, March 10, 12
76. ActorSelection val selection = system.actorSelection("/user/services/*") selection ! "pigdog" Saturday, March 10, 12
77. Supervision class MySupervisor extends Actor { def supervisorStrategy = OneForOneStrategy({ case _: ActorKilledException => Stop case _: ArithmeticException => Resume case _: Exception => Restart case _ => Escalate }, maxNrOfRetries = None, withinTimeRange = None) def receive = { case NewUser(name) => ... = context.actorOf[User](name) } } Scala API Saturday, March 10, 12
78. Supervision class MySupervisor extends Actor { def supervisorStrategy = OneForOneStrategy({ case _: ActorKilledException => Stop case _: ArithmeticException => Resume case _: Exception => Restart case _ => Escalate }, maxNrOfRetries = None, withinTimeRange = None) def receive = { case NewUser(name) => ... = context.actorOf[User](name) } } AllForOneStrategy Scala API Saturday, March 10, 12
79. class FaultTolerantService extends Actor { ... override def preRestart( reason: Throwable, message: Option[Any]) = { ... // clean up before restart } override def postRestart(reason: Throwable) = { ... // init after restart } } Manage failure Scala API Saturday, March 10, 12
80. val buddy: ActorRef = ... val watcher = context.actorOf(Props( new Actor { context.watch(buddy) def receive = { case Terminated(`buddy`) ⇒ … } } )) watch/unwatch Scala API Saturday, March 10, 12
81. Scale out Saturday, March 10, 12
82. New Remote Actors Saturday, March 10, 12
83. val actor = system.actorOf(Props[MyActor], “my-service”) Name Bind the actor to a name Scala API Saturday, March 10, 12
84. Actor name is virtual and decoupled from how it is deployed Deployment Saturday, March 10, 12
85. Deployment If no deployment configuration exists then actor is deployed as local Saturday, March 10, 12
86. Deployment The same system can be configured as distributed without code change (even change at runtime) Saturday, March 10, 12
87. Deployment Write as local but deploy as distributed in the cloud without code change Saturday, March 10, 12
88. Deployment Allows runtime to dynamically and adaptively change topology Saturday, March 10, 12
89. akka { actor { deployment { /my-service { router = "round-robin" nr-of-instances = 3 target { nodes = ["wallace:2552", "gromit:2552"] } } } } } Deployment configuration Saturday, March 10, 12
90. Error Kernel Saturday, March 10, 12
91. Node 1 Node 2 Saturday, March 10, 12
92. ‣ EventBus API ‣ Extensions ‣ ScalaSTM ‣ TypedActor 2.0 More news Saturday, March 10, 12
93. Akka 2.0+ Saturday, March 10, 12
94. ‣ Apache Camel ‣ AMQP ‣ Spring Integration Saturday, March 10, 12
95. Get it and learn more http://akka.io http://typesafe.com Saturday, March 10, 12
96. EOF Saturday, March 10, 12