Legacy applications are everywhere. When should you begin to refactor to a microservices approach, and what are the best ways to approach this challenge? In this chalk talk, we walk through a real-world example of breaking up a monolith.

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Breaking up the Monolith
Tom Whateley
Solution Architect
AWS
A R C 3 0 6
Xavier Hutchinson
Solution Architect
AWS

3. “This is a true story. The events depicted took
place in Queensland in 2017. At the request of
the survivors, the names have been changed.
Out of respect for the dead, the rest has been
told exactly as it occurred.” Fargo

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Our definition of
microservices
Microservices are small, isolated
services, each of which owns their
own data, independently
deployable and scalable, resilient
to failure

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Circa 2013
• 20+ year old legacy monolith
application
• Commenced project to rebuild in
J2EE, aiming to build a web app
to replace legacy
• Stopped in 2016 when they
realized that they were building
another monolith

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Second attempt at
microservices
• Started a discrete backend
modules: Payments & doc
generation
• Updated existing front-end to
use it

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More to do
• New services had new
requirements
• Needed to implement
authentication and authorization

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Database migration
• Migrated legacy application from
Sun/Ingres to Linux/Postgres
Aurora
• Migrated databases from SQL
Server to Postgres Aurora
• Reduced license costs, allowed
separate data stores

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(Aside) monolithic
databases
• Different customer had lots of
“microservices” all pointing to a
single database
• Ended up with a “distributed
monolith,” impacted agility, not
independently deployable

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Authentication (again)
• Update authentication to use
Amazon Cognito to utilize social
capabilities
• Use AWS services wherever
possible, focus on business
functionality
Sony Pictures

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(Aside) S-to-S
authentication
• Different customer
• Service to Service authentication
implemented by AWS Identity
and Access Management (IAM)
and Amazon API Gateway,
independently of user
authentication
• Tied to IAM, make sure this is
done deliberately

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All new services are
serverless microservices
Created a new service/project, using
the following technologies
• HTML5/JavaScript
• API Gateway
• AWS WAF
• Containers – Amazon Elastic
Container Service (Amazon ECS),
AWS Fargate

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More projects delivered
• Two new business capabilities
delivered as microservices
• Pay down technical debt as-you-go
• Debugging issues is getting hard

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Need more
automation
• Starting projects to complete
redevelopment of legacy
application
• Need full CI/CD pipelines for all
projects

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Recap
Microservices are small, isolated services, each of which owns their own
data, independently deployable and scalable, resilient to failure
• Start small
• Continually deliver business value
• Licenses vs. open source
• Authentication & authorization
• Observability
• Deployment strategies (CI/CD)

16. Thank you!
© 2018, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Tom Whateley
tomwh@amazon.com

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