the 6 traits of reactive microservices

IT'S A NEW WORLDYESTERDAY VS TODAY

Traditional applicationarchitectures and

platformsare obsolete.

— Gartner

THE REACTIVE ESSENCE OF A MICROSERVICE1. Isolation

2. Asynchronicity3. Autonomicity

4. Single Responsibility5. Exclusive State

6. Mobility

DIVIDEAND

CONQUER

ISOLATIONTHE FOUNDATION

IT WILL SLICE UP YOUR1. ORGANIZATION2. ARCHITECTURE

Organizations which design systems...are

constrained to produce designs which are

copies of the communication

structures of these organizations.

— Melvin Conway

USE BULKHEADING

BUTWHAT ABOUT THE

TITANIC?

RESILIENCEIS THE ABILITY TO SELF-HEAL, AND REQUIRES

COMPARTMENTALIZATIONOF FAILURE

GOASYNCHRONOUS

ASYNC IO—IS ABOUT NOT BLOCKING THREADS

ASYNC COMMUNICATION—IS ABOUT NOT BLOCKING REQUESTS

ASYNCHRONOUS

IO

WHY IS BLOCKING SO BAD?

SYNCHRONOUS DISPATCH

ASYNCHRONOUS DISPATCH

ASYNCHRONOUSCOMMUNICATION

ASYNC COMMUNICATION ALLOWS DECOUPLING IN

SPACEAND

TIME

ASYCHRONOUS MESSAGE-PASSINGEMBRACES THE CONSTRAINTS OFDISTRIBUTED SYSTEMS

THE WORLD IS GOING STREAMING

ACTAUTONOMOUSLY

PROMISE THEORYLEADS THE WAY

THE WORD 'MICROSERVICE'CONSIDERED HARMFUL

A SERVICE SHOULD DODO ONE THING

AND

DO IT WELL

The Unix philosophy:Write programs that do one thing & do it well.

Write programs to work together.

— Doug McIlroy

BUT WHAT ABOUT

STATE?

OWN YOUR STATE, EXCLUSIVELY

THERE IS NO SUCH THING AS A"STATELESS" ARCHITECTUREIT'S JUST SOMEONE ELSE'S PROBLEM

BOUNDEDCONTEXTS

POLYGLOTPERSISTENCE

The truth is the log.The database is a cache of a subset of the log.

— Pat Helland

FAVOR

EVENT LOGGING

GREAT FIT FOR MESSAGE-PASSING SYSTEMS

> Signal Intent: Use Commands> Publish Facts: Use Events

SINGLE WRITER PRINCIPLE> Minimized Contention

> High throughput & Low latency

EVENT SOURCING

WITH CQRS

AVOIDS THE INFAMOUSOBJECT-RELATIONALIMPEDENCE MISMATCH

STAY MOBILE BUT ADDRESSABLE

But I'll take my time anywhere.

I'm free to speak my mind anywhere.And I'll redefine

anywhere.Anywhere I roam.

Where I lay my head is home.

— Wherever I May Roam by Lars Ulrich, James Hetfield (Metallica)

WHY VIRTUAL ADRESSING?

1. Load-balancing between stateless services2. State replication between stateful services

3. Relocation of a stateful service

REFERENCES SHOULD ALWAYS WORK

SO, THERE YOU HAVE IT

THE 6 TRAITS OF A REACTIVE MICROSERVICE1. Isolation

2. Asynchronicity3. Autonomicity

4. Single Responsibility5. Exclusive State

BY NOW WE SHOULD HAVE A PRETTY GOOD UNDERSTANDING OF WHAT

CHARACTERIZES A SINGLEREACTIVE MICROSERVICE

HOWEVERONE MICROSERVICE

IS NOT OF MUCH USETHEY COME IN SYSTEMS

STAY TUNED FOR EPISODE 3