Reactive Architectures with Microservices

© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.

Sascha Möllering, Solutions Architect, @sascha242

07.11.2017

Reactive Architectures with Microservices


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Why are we here today?


Agenda

• What is Reactive Architecture?• How to build Reactive Architectures in AWS?• Application Architecture• Global Rollout• Q&A

© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.

What is Reactive Architecture?


Front-end server

Internal APIInternal

APIAPI

Poll

Poll

Database

Storage

Queries

Synchronous

User waits for update

N-Tier architecture


Software moves faster today


Traditional style of applications cannot deliver on these requirements any

longer


Responsive

Elastic Resilient

Message-driven

Reactive Applications


Reactive programming“A development model focusing on the observation of data streams, reacting on changes, and propagating them”

Reactive Architecture

Reactive system“An architecture style used to build responsive and robust distributed systems based on asynchronous message-passing.”


Reactive Architecture

• Asynchronous message passing• Non-blocking

• Higher throughput• Effective hardware utilization and lower costs

• Loosely coupled• Location independent• Easy to extend and maintain

• Push-based


Microservices


Microservices should be stateless.

Keep state in external systems.


AvoidHost-Affinity.


Use lightweight protocols for

communication.


Use mechanisms for registration.


How to build Reactive Architectures in AWS?


Example use case

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High Level Architecture


Amazon ECSApplication Load Balancer

Amazon ECR

Kinesis Stream

Kinesis Stream

Lambda function

Lambda function

ElastiCachecluster

Data ingestion

Core data update

Amazon DynamoDB

Core data updates

Data collection



• Amazon ECS and Docker used for the main application

• Resiliency and Elasticity implemented by using Auto Scaling



• AWS Lambda functions• Consume messages• Persist data in NoSQL-store• Update core-data in Redis• Send notifications to main application• Resiliency and Scalability part of the service



• Amazon Kinesis Streams used to decouple components

• Asynchronously push event data to NoSQL-store

• Update core-data in Redis



• Amazon ElastiCache with Redis 3 engine• Multi-AZ setup with failover and one shard• Used to store core-data • Notification channel

• Redis supports pub/sub



• Amazon DynamoDB NoSQL-store used to persist event-data


Application Architecture



Amazon ECR

Kinesis Stream

Kinesis Stream

Lambda function

Lambda function

ElastiCachecluster

Data ingestion

Core data update

Amazon DynamoDB

Core data updates

Data collectionYou are here now!





Picture source: http://vertx.io/docs/guide-for-java-devs/



“Don’t block the event loop!”

- Vert.x golden rule









• HttpVerticle: exposes HTTP endpoint• CacheVerticle: implements L1 cache• RedisVerticle: implements Redis access• KinesisVerticle: messages to Amazon Kinesis Stream


Subscribe to EB

Send prepared data



CacheRulesEverythingAroundMe


Subscribe to EB

Subscribe to Redis channel

Consume data from event bus

Send data to cache verticle



Amazon ECR

Kinesis Stream

Kinesis Stream

Lambda function

Lambda function

ElastiCachecluster

Data ingestion

Core data update

Amazon DynamoDB

Core data updates

Data collection You are here now!



AWS Lambda


Lambda considerations and best practices

AWS Lambda is stateless—architect accordingly• Assume no affinity with underlying compute

infrastructure• Local filesystem access and child process may not

extend beyond the lifetime of the Lambda request


Kinesis event processing

Iterate over batch of events


Global Rollout


16 Regions44 Availability Zones

AWS Global Infrastructure


Global Rollout

AWS CloudFormation


Global Rollout

• Infrastructure as Code• Create and manage resources with CloudFormation

templates• CloudFormation template is used to deploy stacks


Global Rollout


Master Region• One stream of data• One region to process data• Data has to be transferred

inter region

Global Rollout

Distributed Processing• Data processing in every

region• No unified view on data


Summary


Summary

• Reactive Architectures very good fit for AWS Cloud• Microservices improve isolation • AWS offers a lot of services for decoupled application

design• Focus on business requirements, don’t reinvent the

wheel


Thank you!

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Reactive Architectures with Microservices