MicroservicesModern software architecture

About me

● Software start up since 2010

● Professional interest

○ To build big scalable apps

○ Engineering as an art of state

● Fine art photography and bio hacking hobbyist

About nomadays

Tourism software started in 2010 October

Complete rewrite from 2013

Refactored into microservices from 2015

2 main UI:

Backoffice - for company manager

Platform - for travelers

Why do we need microservices?

Monolithic architecture

5000 requests per minute 50 requests per minute

Mostly writes, few reads

Compute heavy

Monolithic application architecture cons

Different non functional requirements (read, write, compute...) & optimized for none

Single points of failure

Overloads your IDE and container

Has physical limit

Monolithic application architecture cons

Monolithic application architecture cons

Monolithic application architecture cons

Scaling applications

Scaling vertical vs horizontal

The scale cube

Y axis scaling & X axis scaling

Microservices

Microservices is a specialisation of and implementation approach for service-oriented architectures (SOA) used to build flexible, independently deployable software systems.

Microservices

The services are easy to replace.Services are organized around capabilities, e.g., user interface front-end, recommendation, logistics,

billing, etc.Services can be implemented using different programming languages, databases, hardware and

software environment, depending on what fits best.Services are small in size, messaging enabled, bounded by contexts, autonomously developed,

independently deployable, decentralized and built and released with automated processes. [7]

Partitioning applications

Partitioning strategies

Too few

Drawbacks of the monolithic architecture

Too many - a.k.a. Nano-service anti-pattern

Runtime overhead

Potential risk of excessive network hops

Potentially difficult to understand system

When partitioning

Focus on building cohesive services that make development and deployment easier… not just tiny services.

- Chris Richardson

Real world example

Amazon (100-150 services to build a page)

Netflix (~600 services)

SoundCloud

Ebay

Uber

…

Nomadays11 microservices, 1 config server, 1 service registry

Client service interaction design

Inter-service communication options

Synchronous HTTP vs asynchronous AMQP

Formats: JSON, XML, Protocol Buffers, Thrift, ...

Pros and cons of messaging

Pros

Decouples client from server

Message broker buffers messages

Supports a variety of communication patterns

Cons

Additional complexity of message broker

Request/reply-style communication is more complex

Pros and cons of HTTP

Pros

Simple and familiar

Request/reply is easy

Firewall friendly

No intermediate broker

Cons

Only supports request/reply

Server must be available

Client needs to discover URL(s) of server(s)

Our technology choice

Netflix OSS

Api gateway: Zuul

Service registry: Eureka

Client side load balancer: Ribbon

Circuit breaker: Hystrix

Reactive programming: RxJava

RabbitMQ

Cloud foundry PAAS

Jenkins CI

...

Zuul, eureka, ribbon.

Circuit breaker: Hystrix

Hystrix dashboard

Lessons learned

Data is different and difficult. Split your database

Reactive programming is necessary. It can be difficult.

It will take time to put pieces together.

Inconsistent failures are SCARY.

Next steps

Event sourcing & cqrs

More reactive programming

Log aggregation

Q&A

Thank you