The emergence of serverless infrastructure and services represents a fundamental shift in how developers approach architecting applications. This is especially relevant in the world of SaaS where systems must efficiently and cost-effectively respond to continually shifting multi-tenant loads and profiles. We’ll conduct an end-to-end review of all the elements of a serverless SaaS architecture that leverages a combination of AWS Lambda, Fargate, and Aurora Serverless. We’ll look at how serverless influence the core elements of your architecture, including tenant isolation, service decomposition, management and monitoring, deployment, and identity.

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Architecting Next Generation Serverless SaaS
Solutions on AWS
Tod Golding
Partner Solutions Architect
Amazon Web Services
A R C 3 2 4

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SaaS and serverless: a natural fit

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No more over-provisioning
Tenants Tenant consumptionCost, scale, performance
Consumption Time

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High level serverless SaaS architecture

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Shared onboarding services

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Serverless authentication and authorization
Amazon
CognitoTenant
JWT token
(user, tenant, role)
Validate tenant,
user, role access

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Tenant throttling strategies
Tenant 1
(Standard Tier)
Tenant 2
(Professional Tier)
Tenant 3
(Premium Tier)
API key(s)
Usage plan

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Compute isolation and serverless
EC2 Instances
EC2 silo model
Tenant 2Tenant 1
ECS Cluster
Tenant 1 Tenant 2
ECS silo model
EC2 Instances
ECS Cluster
How do these
map to serverless?

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Tenant isolation with siloes
Tenant 1 Tenant 2

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Tenant isolation with policies
Tenant 2Tenant 1

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Tenant isolation with tokens
Tenant 1 Tenant 2

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Wrapper-based isolation
var lambdaFunc = require('myModule/mymod.js’);
var lambda = require('lambda-wrapper').wrap(lambdaFunc);
lambda.run(event, function(err, data) {
if (err) {
... handle error
}
... process data returned by the Lambda function
})

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The good news
Tenant 1 Tenant 2
Tenant 2Tenant 1

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Serverless application services
TenantID Name
Tenant-1 Jane Doe
Tenant-4 Mike Doe

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A different scaling mindset
GetOrder()
UpdateOrder()
DeleteOrder()
GetOrder() GetOrder()
UpdateOrder()
Scale
Policy
Policy
Order
Management
Service
Order
Management
Service
Order
Management
Service
Order
Management
Service
POST /orders/712
PUT /orders/42
DELETE /orders/651
GET /orders
Scale

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Hiding away multi-tenant awareness
Multi-tenant data access
Metering&
analytics
Logging

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Flowing tenant context through services
Tenant
Token
Token (HTTP headers)
Metering
Logging
Data Access
Token
Tenant 1 Tenant 2

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State residue for functions
Tenant 1
1
2
Tenant 2

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Serverless and SaaS agility
Scheduled Maintenance
Friday, April 1, 11:00-12:00PM
The system will be down for maintenance this
evening. We apologize for any inconvenience this
may cause.
Close
Achieving zero-downtime on SaaS requires
• Ability to deploy small, decoupled units of functionality
• A strategy that expects and embraces fault tolerance
• A well-defined mechanism for staging and releasing new features
• An approach that enables continual and frequent releases

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Can’t get much smaller than this
Commit
Unit
Test
System
Test
QA Staging Prod
Commit
Unit
Test
System
Test
QA Staging Prod
Commit
Unit
Test
System
Test
QA Staging Prod
GetOrder()
CreateOrder()
UpdateOrder()

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Smaller blast radius = better fault tolerance
• Finer grained functions promote more refined fault tolerance
• More opportunities for implement fallback strategies
• Less exposure and visibility when a service fails
• Greater resilience translates into greater agility
Catalog
Ratings
Checkout
Taxation
CrossSell
Cart
Search

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Servers impact SaaS storage
db.m4.large
db.m4.16xlarge
db.m4.4xlarge
Tenants

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Strategies for addressing compute size
Over provisioning
Load-driven resizing
Tenant 1 Tenant 2
Tenant 1
Tenant 1
Tenant 1

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Pooled storage compute challenges
TenantID Name StartDate
Tenant-1 Jane Doe 01-12-2012
Tenant-4 John Doe 09-01-2015
Tenant-9 Mary Smith 11-04-2017SaaS
Database
Customer table
Tenant 1
Tenants can rapidly saturate and instance
Tenant 2
Tenant 3

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On-demand sizing with Amazon Aurora Serverless
Proxy fleet
Instance Instance Instance
Aurora instances
Application
Storage Storage Storage
• Remove the notion of servers/instances
• All data is kept in highly available
storage volume
• Application talks to a MySQL
compatible endpoint
• Fleet of proxy servers manage, queue
and route database traffic

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Leveraging pooled instances
Instance Instance Instance
Aurora instances
Warm instance pool

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Data partitioning with Amazon Aurora Serverless
Instance
Aurora instance
Tenant 1
Instance
Aurora instance
Tenant 1 Tenant 2
Instance
Aurora instance
Tenant 2
Warm instance pool
Silo partitioning Pool partitioning

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Full stack serverless SaaS
Amazon API Gateway
Aurora Serverless Storage
Tenant 1 Tenant 2
• Brings serverless to relational environments
• Isolation of compute and storage with no
idle costs
• Simplified management and deployment
• Less operational focus on tuning and sizing
policies
• More focus on your application IP
Tenant 1 Tenant 2

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Where does AWS Fargate fit?
Fargate cluster
Tenant 1 Tenant 2
• A more coarse-grained view of serverless
• Often fits the developer mental model
• Can represent a more natural transition for
legacy systems
Tenant 3

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Takeaways
• Use serverless to focus more attention on your IP
• Find the isolation balance that best suits your domain
• Tenant load profile should influence service decomposition
• Find the logical services for data encapsulation
• Consider extending the reach of serverless to storage
• Use serverless DevOps to simplify your zero downtime store
• Serverless and SaaS are a natural match

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Additional SaaS Breakouts
Monday, 11/26
GPSTEC3-2 - SaaS Reference Architectures: A Review of Real World Patterns and Strategies
6:15 PM | Venetian, Level 2, Venetian Theater
Tuesday, 11/27
ARC324 - Architecting Next Generation Serverless SaaS Solutions on AWS (Repeat)
4:00 PM | Venetian, Level 2, Titian 2204
Thursday, 11/29
ARC418 Deconstructing SaaS: Deep Dive into Building Multi-Tenant Solutions on AWS (Repeat)
4:00 PM | Aria, Aria West, Level 3, Ironwood 5
Wednesday, 11/28
ARC418 Deconstructing SaaS: Deep Dive into Building Multi-Tenant Solutions on AWS
12:15 PM | Mirage, Mirage Event Center B

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SaaS Chalk Talks
Monday, 11/26
ARC216 - SaaS Operations: The Foundation of SaaS Agility
11:30 – 12:30 | Venetian, Level 2, Veronese 2406
Tuesday, 11/27
ARC210 - SaaS Jumpstart: A Primer for Launching Your SaaS Journey
9:15 – 10:15 | Venetian, Level 4, Lando 4304
Wednesday, 11/28
ARC419 – Optimizing Your SaaS Solutions on AWS
1:00 – 2:00 | Venetian, Level 3, Murano 3202
ARC326 - Migrating Single-Tenant Applications to Multi-Tenant SaaS
4:00 – 5:00 | Aria West, Level 3, Starvine 7
ARC210 - SaaS Jumpstart: A Primer for Launching Your SaaS Journey
1:45 – 2:45 | Aria West, Level 3, Ironwood 8

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SaaS Chalk Talks
Thursday, 11/29
ARC210 - SaaS Jumpstart: A Primer for Launching Your SaaS Journey
1:45 – 2:45 | MGM, Level 1, South Concourse 105
Friday, 11/30
ARC326 – Migrating Single-Tenant Applications to Multi-Tenant SaaS
10:00 – 11:00 | MGM, Level 1, South Concourse 105
ARC419 – Optimizing Your SaaS Architecture on AWS
1:00 – 2:00 | Venetian, Level 3, Murano 3202

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SaaS Workshops
Monday, 11/26
Hands-on SaaS: Constructing Multi-Tenant Solutions on AWS
4:00 – 6:15 PM | Mirage, Mirage Event Center C3
Friday, 11/30
Hands-on SaaS: Constructing Multi-Tenant Solutions on AWS
9:15 AM – 11:30 AM | Mirage, Mirage Event Center C2

36. Thank you!
© 2018, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Tod Golding
todg@amazon.com

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