Above the Clouds: Introducing Akka Jonas Bonr CTO Typesafe - - PowerPoint PPT Presentation

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Above the Clouds: Introducing Akka Jonas Bonr CTO Typesafe - - PowerPoint PPT Presentation

Feb 28, 2024 260 likes •1.2k views

Above the Clouds: Introducing Akka Jonas Bonr CTO Typesafe Twitter: @jboner torsdag 13 oktober 11 The problem It is way too hard to build: 1. correct highly concurrent systems 2. truly scalable systems 3. fault-tolerant systems that

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Above the Clouds: Introducing Akka

Jonas Bonér

CTO Typesafe Twitter: @jboner torsdag 13 oktober 11
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The problem

It is way too hard to build:

  • 1. correct highly concurrent systems
  • 2. truly scalable systems
  • 3. fault-tolerant systems that self-heals

...using “state-of-the-art” tools

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akka

Introducing

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Vision

Simpler

Concurrency Scalability Fault-tolerance

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SLIDE 5

Vision

...with a single unified

Programming model Runtime service

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SLIDE 6

Manage system overload

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SLIDE 7

Scale up & Scale out

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SLIDE 8

Replicate and distribute for fault-tolerance

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SLIDE 9

Transparent load balancing

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SLIDE 10

CORE SERVICES

ARCHITECTURE

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SLIDE 11

ADD-ON MODULES

ARCHITECTURE

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SLIDE 12

ARCHITECTURE

CLOUDY AKKA

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SLIDE 13 FINANCE
  • Stock trend Analysis & Simulation
  • Event-driven messaging systems
BETTING & GAMING
  • Massive multiplayer online gaming
  • High throughput and transactional
betting TELECOM
  • Streaming media network gateways
SIMULATION
  • 3D simulation engines
E-COMMERCE
  • Social media community sites

SOME EXAMPLES:

WHERE IS AKKA USED?

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SLIDE 14

What is an Actor?

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SLIDE 15 Behavior State Actor torsdag 13 oktober 11
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SLIDE 16 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 17 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 18 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 19 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 20 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 21 Behavior State Actor torsdag 13 oktober 11
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SLIDE 22 Event-driven Thread Behavior State Actor torsdag 13 oktober 11
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SLIDE 23

Akka Actors

  • ne tool in the toolbox
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SLIDE 24 case object Tick class Counter extends Actor { var counter = 0 def receive = { case Tick => counter += 1 println(counter) } }

Actors

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SLIDE 25

val counter = actorOf[Counter]

Create Actors

counter is an ActorRef

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val counter = actorOf[Counter].start

Start actors

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val counter = actorOf[Counter].start counter.stop

Stop actors

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counter ! Tick

Send: !

fire-forget

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SLIDE 29 // returns a future val future = actor ? Message future onComplete { f => f.value }

Send: ?

returns the Future directly

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SLIDE 30

Future

val future1, future2, future3 = Future.empty[String] future1.await future2 onComplete { f => ... } future3
  • nResult { ... }
  • nException { ... }
  • nTimeout { ... }
future1 foreach { ... } future1 map { ... } future1 flatMap { ... } future1 filter { ... } torsdag 13 oktober 11
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SLIDE 31 val f0 = Future { ... } Future.firstCompletedOf(futures) Future.reduce(futures)((x, y) => ..) Future.fold(zero)(futures)((x, y) => ...) Future.find { ... } Future.sequence { ... } Future.traverse { ... }

Future

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SLIDE 32

Promise

promise1.completeWithResult(...) promise2.completeWithException(...) promise3.completeWith(promise2)

The write side of the Future

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SLIDE 33

Dataflow

import Future.flow val x, y, z = Promise[Int]() flow { z << x() + y() println("z = " + z()) } flow { x << 40 } flow { y << 2 } torsdag 13 oktober 11
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SLIDE 34 class SomeActor extends Actor { def receive = { case User(name) => // use reply self.reply(“Hi ” + name) } }

Reply

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SLIDE 35

HotSwap

self become { // new body case NewMessage => ... }

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SLIDE 36

HotSwap

self.unbecome()

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SLIDE 37 class MyActor extends Actor { self.dispatcher = Dispatchers .newPinnedDispatcher(self) ... } actor.dispatcher = dispatcher // before started

Set dispatcher

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SLIDE 38

Remote Actors

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SLIDE 39 // use host & port in config Actor.remote.start() Actor.remote.start("localhost", 2552)

Remote Server

Scalable implementation based on NIO (Netty) & Protobuf

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SLIDE 40 import Actor._ remote.register(“service:id”, actorOf[MyService])

Register and manage actor on server client gets “dumb” proxy handle server part

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SLIDE 41 val service = remote.actorFor( “service:id”, “darkstar”, 9999) service ! message

client part

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SLIDE 42

Problem

Deployment (local vs remote) is a dev decision We get a fixed and hard-coded topology Can’t change it dynamically and adaptively

Needs to be a deployment & runtime decision

Remoting in Akka 1.2

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SLIDE 43

Clustered Actors

(in development for upcoming Akka 2.x)

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SLIDE 44 val actor = actorOf[MyActor](“my-service”)

Address

Bind the actor to a virtual address

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SLIDE 45
  • Actor address is virtual and decoupled from how it

is deployed

  • If no deployment configuration exists then actor is

deployed as local

  • The same system can be configured as distributed

without code change (even change at runtime)

  • Write as local but deploy as distributed in the

cloud without code change

  • Allows runtime to dynamically and adaptively

change topology

Deployment

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SLIDE 46 akka { actor { deployment { my-service { router = "least-cpu" failure-detector = "accrual" clustered { nr-of-instances = 3 replication { storage = "transaction-log" strategy = "write-through" } } } } } }

Deployment configuration

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SLIDE 47
  • Subscription-based cluster membership service
  • Highly available cluster registry for actors
  • Automatic cluster-wide deployment
  • Highly available centralized configuration service
  • Automatic replication with automatic fail-over upon

node crash

  • Transparent and user-configurable load-balancing
  • Transparent adaptive cluster rebalancing
  • Leader election
  • Durable mailboxes - guaranteed delivery

The runtime provides

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SLIDE 48 Akka Node torsdag 13 oktober 11
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SLIDE 49 Akka Node val ping = actorOf[Ping](“ping”) val pong = actorOf[Pong](“pong”) ping ! Ball(pong) torsdag 13 oktober 11
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SLIDE 50 Akka Node val ping = actorOf[Ping](“ping”) val pong = actorOf[Pong](“pong”) ping ! Ball(pong) Ping Pong torsdag 13 oktober 11
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SLIDE 51 Akka Node Akka Cluster Node Ping Pong torsdag 13 oktober 11
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SLIDE 52 Akka Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong torsdag 13 oktober 11
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SLIDE 53 Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong torsdag 13 oktober 11
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SLIDE 54 akka { actor { deployment { ping {} pong { router = "round-robin" clustered { nr-of-instances = 3 } } } } } Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong torsdag 13 oktober 11
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SLIDE 55 akka { actor { deployment { ping {} pong { router = "round-robin" clustered { nr-of-instances = 3 } } } } } Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong torsdag 13 oktober 11
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SLIDE 56 akka { actor { deployment { ping {} pong { router = "round-robin" clustered { nr-of-instances = 3 } } } } } Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong Pong Pong torsdag 13 oktober 11
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SLIDE 57 akka { actor { deployment { ping {} pong { router = "round-robin" clustered { nr-of-instances = 3 } } } } } ZooKeeper ZooKeeper ZooKeeper Ensemble Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Akka Cluster Node Ping Pong Pong Pong torsdag 13 oktober 11
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SLIDE 58

Let it crash fault-tolerance

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SLIDE 59

The

Erlang

model

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SLIDE 60

9 nines

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...let’s take a standard OO application

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SLIDE 62 torsdag 13 oktober 11
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Which components have critically important state and explicit error handling?

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SLIDE 64 torsdag 13 oktober 11
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Classification of State

  • Scratch data
  • Static data
  • Supplied at boot time
  • Supplied by other components
  • Dynamic data
  • Data possible to recompute
  • Input from other sources; data

that is impossible to recompute

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Classification of State

  • Scratch data
  • Static data
  • Supplied at boot time
  • Supplied by other components
  • Dynamic data
  • Data possible to recompute
  • Input from other sources; data

that is impossible to recompute

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SLIDE 67

Classification of State

  • Scratch data
  • Static data
  • Supplied at boot time
  • Supplied by other components
  • Dynamic data
  • Data possible to recompute
  • Input from other sources; data

that is impossible to recompute

Must be protected by any means

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SLIDE 68

Fault-tolerant

  • nion-layered

Error Kernel

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SLIDE 69 Error Kernel torsdag 13 oktober 11
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SLIDE 70 Error Kernel torsdag 13 oktober 11
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SLIDE 71 Error Kernel torsdag 13 oktober 11
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SLIDE 72 Error Kernel torsdag 13 oktober 11
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SLIDE 73 Error Kernel torsdag 13 oktober 11
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SLIDE 74 Error Kernel torsdag 13 oktober 11
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SLIDE 75 Error Kernel torsdag 13 oktober 11
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SLIDE 76 Error Kernel torsdag 13 oktober 11
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SLIDE 77 Error Kernel torsdag 13 oktober 11
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SLIDE 78 Error Kernel torsdag 13 oktober 11
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SLIDE 79 Error Kernel torsdag 13 oktober 11
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SLIDE 80 Error Kernel torsdag 13 oktober 11
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SLIDE 81 Error Kernel torsdag 13 oktober 11
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SLIDE 82 Error Kernel torsdag 13 oktober 11
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SLIDE 83 Error Kernel torsdag 13 oktober 11
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SLIDE 85 torsdag 13 oktober 11
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SLIDE 86 Node 1 Node 2 torsdag 13 oktober 11
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SLIDE 87

link(actor) unlink(actor) startLink(actor) spawnLink[MyActor]

Linking

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SLIDE 88

AllForOneStrategy( errors, maxNrOfRetries, withinTimeRange) OneForOneStrategy( errors, maxNrOfRetries, withinTimeRange)

Fault handlers

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SLIDE 89 class ¡Supervisor ¡extends ¡Actor ¡{ ¡ ¡faultHandler ¡= ¡AllForOneStrategy( ¡ ¡ ¡ ¡List(classOf[IllegalStateException]) ¡ ¡ ¡ ¡ ¡5, ¡5000)) ¡ ¡def ¡receive ¡= ¡{ ¡ ¡ ¡ ¡case ¡Register(actor) ¡=> ¡link(actor) ¡ ¡} }

Supervision

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SLIDE 90 class FaultTolerantService extends Actor { ...
  • verride def preRestart(reason: Throwable) = {
... // clean up before restart }
  • verride def postRestart(reason: Throwable) = {
... // init after restart } }

Manage failure

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SLIDE 91

AMQP Dataflow Security

...and much much more

HTTP Guice scalaz FSM STM Spring Camel OSGi Microkernel

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SLIDE 92

Get it and learn more

http://akka.io

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SLIDE 93

EOF

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