Microsoft Project OrleansVirtual Actors Set the Stage for Performance, Reliablity, and Scale

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Presentation Roadmap

• Demo & Solution overview

• Overview of Actor Model

• Introducing Orleans and virtual actors!

• Basics of Orleans

• Benefits of Orleans

• Advanced topics

College Class Scheduling

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3 Find classes

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So what’s all the hype with actors?

Well… Actors are funny!Wait… Sorry… wrong actors.

Let’s Talk Actor Model Theory

• Concurrent digital computation

• Heavily influenced by work in the field of process calculi (or process algebra)• Parallel composition

• Communication

• Theory within computer science that dates back to the 1973

• Heavily influenced by packet switched networks

Actor Model

• Characteristics of actors• Isolated

• Single-threaded

• Inherently concurrent

• Processes interact with actors through queues

• Actors are adressable

Reference: http://blog.kjempekjekt.com/2013/02/16/actor-model-i-f-ved-hjelp-av-mailboxprocessor/

Actor Model – Mailbox Example

• Characteristics of actors• Isolated state

• Data locality

• Locality• There is no simultaneous

change in multiple locations

• Message driven

• Actors are addressableReference: http://3.bp.blogspot.com

Actor Models and Frameworks

• .NET • Actor Framework • NAct• Retlang• PostSharp• Akka.NET

• Java and Skala• Akka (toolkit)

• Erlang (Actor programming languages)• Common complaints

• Actors are often not usefully typed• Actors don’t always compose very well

Thank you Chris for the walk down memory lane, but…

What’s all this have to do with Orleans?

Actors

Introducing Virtual Actors

Teacher Student

Class Subject

Silos Silos are hostable containers for virtual actors.- Orleans Runtime- Azure- On-premise

Hybrid Hosting

Azure

• Virtual actors are called grains• Concurrent components

• State

• Behavior

• Actor-based

• Silos communicate through Orleans conduit

• Silos are hosted via Orleans runtime• Azure

• Windows

• Applications

• Grains communicate through message passingReference:

http://research.microsoft.com/en-us/projects/orleans/

Orleans Grains

Grains

Grain Interface

Silos

ImplementsProvides

Grain Factory

Grain References

Use

Clients

Orleans Runtime

Creating the Interface

Establishes this as a grain interface that is referenced through a unique GUID

All communications with grains are implemented with Task or Task<T>

All grains require a grain interface

• Grain interface shared between client and server

• Implementations of grains inherit from a grain interface

• Grains always return either Task or Task<T>

• Grains are identified by a unique identifier:• IGrainWithGuidKey

• IGrainWithStringKey

• IGrainWithLongKey

GrainGrain

InterfaceGrain

Interface

Creating the Grain

Implements our IStudentinterface and inherits from underlying Orleas.Grain

Grain Implementation

Orleans provides several helpers for managing Tasks

Local state only accessible from within grain

No state is ever shared between grains or clients

Generate Task<string> from the string you wish to return

Running Your First Demo

• Download and install the Orleans SDK

• May also want to grab the latest Azure SDK at this time

• Create a grain interface project

• Create a grain collection project

• Create a DevTest silo using the VS project template

• Create a grain interface and corresponding grain

• Configure the client and server configuration files

• Run it!

Demo TimeCreating a Standalone Grain Dev/Test Silo

Demo TimeImplementing Grains in Azure

Recap

• Actors are isolated single-threaded components

• Orleans grains are like actors, but have differences (virtual actors)

• Grains encapsulate both state and behavior

• Developer interaction with grains is very familiar• Object instances are similar grain references

• Runtime handles complexities that other actor frameworks do not:• Actor placement and load balancing• Deactivation of unused actors• Actor recovery after server failures

• Indirection handled via a distributed directory

This all looks really cool, but come on Chris…

What’s the point? Why should I use this?

Here’s Why

• Grains are• Low latency

• High availability

• Supremely scalable

• Promote reliability

• Extremely performant (will be discussed later)

• 3-tier architecture has limitations• Throughput limits of the storage layer

• Storage layer has limited scalability due

• Storage layer that has to be consulted for every request

Orleans vs. Multi-Server 3-TierTi

me

(R

esp

on

se)

Consumption (Transactions)

Orleans Architecture

3-Tier Architecture

Response time increases exponentially once resources begin to become strained

Orleans does suffer increased latency as it scales it’s silos

Approximately even at low levels of consumption

Come on… Let’s get into some more Advanced topics already!!!

Demo TimeImplementing Grain Persistence

Demo TimePassing Grain References

Orleans is Dynamic

• Providers• Azure Table

• SQL Server

• Memory (Grain)

• Roll your own

• Custom Serializers

• Runtime Monitoring• Performance counters

• Silo statistics and metrics tables

• Liveness Provider • Membership Table Grain

• Azure Table

• SQL Server

• Hosting• Stand-alone Silo

• On-Premise Deployment

• Azure

You may feel at this point that the framework is too new…

Has it really been tested in the field?Who’s really using this?

Questions?