WHEN THE MONOLITH COLLAPSES

Henning Teek

PREVENT PITFALLS WHILE MIGRATING TO MICROSERVICES

August 2019

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ABOUT ME

Henning Teek Senior Consultant / Cloud Native Developer

Storm Reply is Amazon AWS Premier Consulting Partner and is the company in the Reply group specialized in the design and implementation of innovative Cloud-based solutions and services.

• Software Architecture • Software Development • Build Management • CI / CD • DevOps

• Microservices • Databases • Event Driven Architecture • Domain Driven Design

• Conclusion

TODAY‘S AGENDA

MICROSERVICESFrom a monolith to multiple microservices

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MONOLITH VS MICROSERVICES

Does everythingMONOLITH

Does one thingMICROSERVICE

PROS

• Loose coupling • Scalability • Autonomy • Small teams

• Complexity • Eventual Consistency • Resource consumption

MICROSERVICESWhy?

CONS

• Build automation • Continuous Integration (CI) • Continuous delivery and deployment (CD)

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PREREQUESITESDon‘t even start without it!

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MONOLITH TO MICROSERVICEFirst steps

Loose coupling Scalability Autonomy Small teams

- - - - - - - -

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MONOLITH TO MICROSERVICEFirst steps

Loose coupling Scalability Autonomy Small teams

- - - -

DATABASESWhat about my data?

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DATABASE PER SERVICEDon’t touch my data!

- - - -

Loose coupling Scalability Autonomy Small teams

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DATABASE PER SERVICEDon’t touch my data!

Loose coupling Scalability Autonomy Small teams

+ + + + + +

PROS

• Flexibility • Performance

• Complexity

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POLYGLOT PERSISTENCERelational isn‘t always the answer!

CONS

RELATIONAL• Aurora • RDS • Redshift

• Dynamo DB • Document DB

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MANAGED SERVICES AWS Purpose-Built Databases

KEY-VALUE DOCUMENT

IN-MEMORY• Elasticache Redis • Elasticache

Memcached

• Neptune

GRAPH

• Timestream

TIME SERIES

EVENT DRIVEN ARCHITECTUREDon‘t ask, just listen!

+ + + + + +

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MESSAGE QUEUETo whom it may concern!

Loose coupling Scalability Autonomy Small teams

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MESSAGE QUEUETo whom it may concern!

Loose coupling Scalability Autonomy Small teams

+ + + + + + + +

PROS

• Loose coupling • Availabilty • Communication

patterns

• Complexity

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MESSAGINGHey you! Something happened!

CONS

AMAZON MQ• Apache Active MQ • JMS, NMS, AMQP, STOMP,

MQTT and WebSocket • Point-To-Point • Publish-Subscribe

• Standard / FIFO • High throughput • At-Least-Once Delivery • Exactly-Once Processing

• AWS Services as Source • Message Filtering / Fanout • Encryption • Mobile Push / SMS

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MANAGED SERVICES AWS Purpose-Built Messaging

AMAZON SQS AMAZON SNS

AMAZON PINPOINT• Customer centered • Email, Voice, Push

Notification and SMS • Audience Management • Campaings

• Real-time Video / Data • Scalable / Durable • Data Firehose • Data Analytics

AMAZON KINESIS

• Serverles Event Bus • Built-In / Custom Sources • At-Least-Once Delivery • IAM Integration

AMAZON EVENTBRIDGE

DOMAIN DRIVEN DESIGN

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EVENT SOURCINGHistory matters!

Status Total …

101

Shipped 1054.40 …

OrderCreated

OrderApproved

…

OrderShipped

Order 101

PROS

• Simplicity • Audit Log • Temporal Queries

• Queries

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EVENT SOURCINGHistory matters!

CONS

PROS

• Separation of concerns

• Multiple views

• Complexity • Code duplication • Eventual consistency

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CQRSCommand Query Responsibility Segregation

CONS

CONCLUSION

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CONCLUSION

• Database per Service• Polyglot persistence1DATABASES

• Loose coupling • Availabilty2EVENT DRIVEN

• Reduce complexity • Availabilty 3MANAGED SERVICES

• Optimised views • Audit log• Temporal queries

4DOMAIN DRIVEN DESIGN

THANK YOU