Image by Mike Rohde

in the Cloud and at ScaleYan Cui (@theburningmonk)F#

Who is Gamesys?

•Founded in 2001

•#1 in the UK

• Handle $5 Billion in turnover annually

•First company to launch real money gaming on Facebook

•Employ 1,000 globally

Running in the Cloud, at Scale

• 1 Million DAU

• 250 Million requests/day

• 7 Billion rows of analytics events/month

• 2 TB of analytics data/month

Running in the Cloud, at Scale

• 100% cloud hosted

• AWS for Game services

• Google App Engine for back-office services

• NoSQL databases– DynamoDB, CouchBase, Redis, Neo4j, ...

• Google BigQuery for analytics

What is the Cloud?

Cloud computing is an expression used to describe a variety of computing concepts that involve a large number of computers connected through a real-time communication network such as the Internet....

Such virtual servers do not physically exist and can therefore be moved around and scaled up (or down) on the fly without affecting the end user - arguably, rather like a cloud.

- Wikipedia

What is the Cloud?

IaaSVMs, load balancers, storage, ...

PaaSRuntime,

database, web servers, ...

SaaSVirtual desktop,

games, emails, ...

Why the Cloud?

• Trade capital cost with operating cost

• Lower operating cost

• Elastic scaling

• Speed and agility

• Focus on what differentiates your product

• Global infrastructure for your global audience

Why the Cloud - Scalability

• Scale up

• Scale out

• Scale everything!– Your architecture is as scalable as its least scalable part

• Scalability != simple choice of language/framework

Travel, Collect, Craft!

Trap Monsters

Stateful Server

Elastic Load Balancer

S3

Auto scaling Group

Server A Server B

...

EC2

CloudFront

Stateful Server

• Need to ensure Server affinity– All calls need to be routed to the affined server

• Need to balance load– Session lengths vary greatly– Some players are more active than others– Need to avoid hot spots

• Need to avoid players hogging a server– Need to be able to scale down!

Stateful Server

• Persist player state after short inactivity

• Move player to another server after persistence

Why Stateful Server?

• 500% efficiency increase

• 60% reduction in avg latency

• Fewer game servers

• No CouchBase cluster

• Huge saving on cost

The Actor Model

An actor is the fundamental unit of computation which embodies the 3 things

• Processing• Storage• Communication

that are essential to computation.

-Carl Hewitt*

* http://bit.ly/HoNHbG

The Actor Model

• Everything is an actor

• An actor has a mailbox

• When an actor receives a message it can:– Create new actors– Send messages to actors it has addresses for– Designate how to handle the next message it receives

Stateful Server

• Gatekeeper– Manages the local list of active workers– Spawns new workers

• Worker– Manages the states for a player– Optimistic locking– Persist state after period of inactivity

Stateful Server

Game Server

Player A

Player B

S3Worker C

Worker B

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Asynchronous

Stateful Server

Game Server

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Worker B

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Stateful Server

Game Server

Player A

Player B

S3Worker C

Worker B

Gatekeeper

Worker A

Requ

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Stateful Server

Game Server

Player A

Player B

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Stateful Server

Game Server

Player A

Player B

S3Worker C

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error

MailboxProcessor<Message>

Async<Message option>

switch state

Why F#?

• Time to Market

• Efficiency

• Correctness

• Complexity

Why F#?

• Agents– No locks– Asynchronous message passing– Each actor is self-contained and easier to reason with

• Pattern matching– Clear and concise way to handle all branch conditions

Why F#?

• Async Workflows– Non-blocking IO– Convert synchronous code into asynchronous code with

minimal code changes– Similar to C# 5’s async-await feature, but available in F#

since 2007!

Thank You!

JackpotJoy Slotshttp://apps.facebook.com/jackpotjoyslots

Bingo Lanehttp://apps.facebook.com/bingolane

Here Be Monstershttp://apps.facebook.com/herebemonsters

Building a MMORPGhttp://bit.ly/1hjqoL8http://slidesha.re/18MD4XY

Google I/O 2013 – Here Be BigQueryhttp://bit.ly/1fHjbce