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AWS provides a platform that is ideally suited for deploying highly available and reliable systems that can scale with a minimal amount of human interaction. This talk describes a set of architectural patterns that support highly available services that are also scalable, low cost, low latency and allow for agile development practices. We walk through the various architectural decisions taken for each tier and explain our choices for appropriate AWS services and building blocks to ensure the security, scale, availability and reliability of the application.
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Dan Cuddeford and Matthew Trescot
Building Web-Scale Applications with AWS
Enterprise Solutions Architect and Solutions Architect
I am Barack Obama, Ask me anything
Reddit Needed to Scale for a special guest
• 2,987,307 pageviews on the day of the IAmA • President Obama’s user page received 428,004
pageviews on the day of the IAMA • Added 60 dedicated instance to handle the increased
load • At peek transfering 48 MB/s to the internet
While You Scale
• Architect for Failure
– Failures do happen
• Architect with Security
– Security must happen
Why Is Scale Important?
Self
Hosting Waste
Customer
Dissatisfaction
Actual demand
Predicted Demand
Rigid Elastic
Actual demand
AWS
Regions and Storage
Where and What
US-WEST (Oregon) EU-WEST (Ireland)
ASIA PAC (Tokyo)
ASIA PAC
(Singapore)
US-WEST (N. California)
SOUTH AMERICA (Sao Paulo)
US-EAST (Virginia)
AWS GovCloud (US)
ASIA PAC (Sydney)
Regions
US-WEST (Oregon)) EU-WEST (Ireland)
ASIA PAC (Tokyo)
ASIA PAC
(Singapore)
US-WEST (N. California)
SOUTH AMERICA (Sao Paulo)
US-EAST (Virginia)
AWS GovCloud (US)
ASIA PAC (Sydney)
Availability Zones
Storage Types
Ephemeral Storage
• (Almost) every instance has them
• Fast
• Cheap
• Volatile
Elastic Block Storage
• 1GB to 1TB
• Snapshot-able
• You choose the IOPS
• Good for random IO
Storage Types
S3
• (Almost) infinitely durable
• Infinitely scalable
• CloudFront integration
Glacier
• (Almost) infinitely durable
• Infinitely scalable
• Cheapest
Storage Types
Database
• Readily queryable
• Consistency/performance options
SQS
• Logic built-in
• Infinitely scalable
• Good for small blobs and write/read
once
Application Scaling
Wide and Proud
Loose coupling sets you free!
• The looser they're coupled, the bigger they scale
– Independent components
– Design everything as a black box
– Decouple interactions
– Load-balance clusters
Controller A Controller B Controller C
Controller A Controller B Controller C
Q Q Q
Tight Coupling
Use Amazon SQS as Buffers
Loose Coupling
Allows for Parallel Processing and Failure
• Fan out
• Use varied instance types
• Use varied billing models
Allows for Parallel Processing and Failure
Lets you Auto Scale
Auto Scaling Automatic resizing of compute clusters based on demand
Trigger auto-
scaling policy
Feature Details
Control Define minimum and maximum instance pool sizes and when scaling and cool down occurs.
Integrated to Amazon CloudWatch
Use metrics gathered by CloudWatch to drive scaling.
Instance types Run Auto Scaling for On-Demand and Spot Instances. Compatible with VPC.
as-create-auto-scaling-group MyGroup
--launch-configuration MyConfig
--availability-zones eu-west-1a
--min-size 4
--max-size 200
…and Spread the Load
Elastic Load Balancing • Create highly scalable applications
• Distribute load across EC2 instances
in multiple availability zones Feature Details
Available Load balance across instances in multiple Availability Zones
Health checks Automatically checks health of instances and takes them in or out of service
Session stickiness Route requests to the same instance
Secure sockets layer Supports SSL offload from web and application servers with flexible cipher support
Monitoring Publishes metrics to CloudWatch
But usually some state has to reside somewhere
Cookies in browser
Memory-resident session manager
Session database
Framework-provided session handler
So this store of state needs to be…
Performant
Scalable
Reliable
Where should session state reside?
Trigger auto-
scaling policy
Session State Service
Not Here
Here State must reside OUTSIDE
the scope of the elements you wish to scale
And what do I build it on?
The state service itself must be well architected
IAM Temporary Security Credentials
• Use Cases
Identity Federation to AWS APIs
Mobile and browser-based applications
Consumer applications with unlimited users
• Scales to millions of users
– No need to create an IAM identity for every user
AWS Account Credentials
IAM User
Temporary Security
Credentials
The IAM Hierarchy of Permissions
Permissions Example
Unrestricted access to all enabled services and resources
Action: * Effect: Allow Resource: * (implicit)
Access restricted by Group and User policies
Action: [‘s3:*’, ‘sts:Get*’] Effect: Allow Resource: *
Access restricted by generating identity and further by policies used to generate token
Action: [ ‘s3:Get*’ ] Effect: Allow Resource: ‘arn:aws:s3:::userbucket/*’
AWS Application Management Solutions
Elastic Beanstalk OpsWorks CloudFormation EC2
Convenience Control
Higher-level Services Do it yourself
Data Tier Scaling
The bane of the Architect’s existence
Vertical Scaling
“We’re gonna need a bigger box”
• Simplest approach
• Can now leverage PIOPs
• High I/O instances
• Easy to change instance sizes
• Will hit an endpoint eventually
hi1.4xlarge
m2.4xlarge
m1.small
Master/Slave Horizontal Scaling
• Reasonably simple to adapt to
• Can now leverage PIOPs
• Easy to change instances sizes
• Will hit an endpoint eventually
Sharded Horizontal Scaling
Hash Ring
A
B C
D
• More complex at the application layer
• ORM support can help
• No practical limit on scalability
• Operation complexity/sophistication
• Shard by function or key space
• RDBMS or NoSQL
Horizontal Scaling – Fully Managed
DynamoDB • Provisioned throughput NoSQL database
• Fast, predictable performance
• Fully distributed, fault tolerant architecture
• Considerations for non-uniform data
Feature Details
Provisioned throughput
Dial up or down provisioned read/write capacity.
Predictable performance
Average single digit millisecond latencies from SSD-backed infrastructure.
Strong consistency Be sure you are reading the most up to date values.
Fault tolerant Data replicated across Availability Zones.
Monitoring Integrated to CloudWatch.
Secure Integrates with AWS Identity and Access Management (IAM).
Elastic MapReduce
Integrates with Elastic MapReduce for complex analytics on large datasets.
Petabyte-Scale Data Warehousing Feature Details
Optimized for Data
Warehousing
Redshift uses a variety of innovations to obtain very high query performance on datasets ranging in size from hundreds of gigabytes to a petabyte or more.
Scalable Easily scale the number of nodes in your data warehouse up or down as your performance or capacity needs change
Fault tolerant Data replicated across Availability Zones.
Monitoring Integrated to CloudWatch.
Secure Encrypt data in transit and at rest. Can also be run in VPC to isolate your data warehouse cluster.
S3 intergration Loads data in parallel to each node from S3.
Elastic MapReduce
Integrates with ERM via Data Pipeline.
Summary
• Use these techniques (and many, many others) situationally
• Awareness of the options is the first step to good design
• Scaling is the ability to move the bottlenecks around to the
least expensive part of the architecture
• AWS makes this easier – so your application is not a victim of
its own success
