building microservice architectures(neal ford)

BUILDING MICROSERVICE ARCHITECTURES

@neal4d nealford.com

AGENDA

denitions

engineeringcharacteristics

what problem

Conways Laworganizations which design systems ... are constrained to produce designs which are

copies of the communication structures of these organizations

Melvin Conway

The Inverse Conway Maneuver Domain/Architecture Isomorphism

Organized Around Business Capabilities

Coupling Metrics

code artifact

afferent efferentx i t

X-Rayxray.inf.usi.ch/xray.php

Class Dependency

Package Dependency

Azureus Packages

FilteredAzureus Packages

From a Real Monolith

Name withheld by request

Package level coupling from a real monolith

Attempting to generate class

diagram crashed x-ray.

Software architecture represents the

tension between coupling & cohesion.

versusACID BASE

ACID

Atomic Consistent Isolated Durable

BASE

Basic Availability Soft-state Eventual Consistency

# of users

because CAP Theoremwww.julianbrowne.com/article/viewer/brewers-cap-theorem

Formal proof: http://lpd.ep.ch/sgilbert/pubs/BrewersConjecture-SigAct.pdf

As your system becomes more distributed, prefer BASE to ACID

http://www.eaipatterns.com/docs/IEEE_Software_Design_2PC.pdf

http://highscalability.com/blog/2013/5/1/myth-eric-brewer-on-why-banks-are-base-not-acid-

availability.html

AGENDA

denitions


what problem

What Traditional SOA Got RightBreaking monoliths into services

Focus on integration over internal coupling

Prefer BASE to ACID

What Traditional SOA Missed

Architecture is abstract until operationalized.

Impact of Conways Law

The folly of trying to build Uber services (Customer) Didnt support easy change (ESB pattern)

support Microservice is the rst

architectural style developed post-Continuous Delivery.

AGENDA

denitions


what problem

Monoliths vs. Microservices

user interface

server-side

DBA

Orders

Shipping

Catalog

Products, not Projects

projects:

products:

s You build it, you run it

Smart Endpoints, Dumb Pipes

as decoupled & cohesive as possible inspired by Unix lters/pipes transport: HTTP messaging over lightweight bus

Prefer Choreography to Orchestration

traditional SOA / ESB pattern

Because Conways Law!Consumer Driven Contracts

pack of enterprise architects

http://martinfowler.com/articles/consumerDrivenContracts.htmlConsumer Driven Contracts

Prefer REST over SOAP

REST is less brittle at integration points

SOAP = RPC

Standardize on integration, not platform

embrace polyglot solutions where sensible

too few languages/platforms

too many languages/platforms

Sam Newman

Building MicroservicesDESIGNING FINE-GRAINED SYSTEMS

Standardize in the gaps between services - be exible about what

happens inside the boxes


but dont go crazy

Sam Newman


Have one, two or maybe three ways of integrating, not 20.

Sam Newman


Pick some sensible conventions, and stick with them.

Microservice architectures promote coupling from application to integration architecture.

explicit about coupling

forces coarser- grained coupling

engineering safety nets

undisciplined coupling = messcoupling dynamics become integration issues

Decentralized Data Management

ACID versus BASE

Sam Newman


Avoid distributed transactions if at all possible

Decentralized Governance

Decentralized Governance

Enterprise architects suer from less pressure to make the correct choice(s)

in microservice architectures.

Small, Single Responsibility

small enough to t in your head

rewrite over maintain

(101000 LOC)-ish / service

single responsibility

How Big?


partition along natural boundaries

nd a balance between standardization and freeforall

transactional

domain

organizational

Partitioning by Existing Coupling

God Object: an object that knows too much or does too much

Asynchronicity

Prefer timely partial over slow complete

return optimized for ranking/aggregation,

not display

Traditional Monolith

Model

User Interface

CQRS

http://codebetter.com/gregyoung/2010/02/16/cqrs-task-based-uis-event-sourcing-agh/

Query Model

Command Model

User Interface

ReportingQuery Model

Command Model

User Interface

. . .

AGENDA

denitions


what problem

Design For Failure

clients must respond gracefully to provider failure

aggressive monitoring: - business relevant - architectural - semantic

Monitoring

Sam Newman


You have to get much better at monitoring.

Sam Newman


You are not a badass if you use an SSH Multiplexer!

Aggregating Monitors

Response TimeResponse Time

Response Time

Sam Newman


Capture metrics, and logs, for each node, and aggregate them

to get a rolled up picture.

Aggregating Monitors

Synthetic Transactions

Sam Newman


Use synthetic transactions to test production systems.

Correlation IDs ID: 123

ID: 123

ID: 123

Sam Newman


Use correlation IDs to track down nasty bugs

Engineering Consistency

service behavior

integration

downstream

metrics

Sam Newman


Consider Service Templates to make it easy to do the right

thing!

SCM RepositoriesPrefer repository per service to monolithic

repository

Integrate via continuous integration

Testing Microservices

http://martinfowler.com/articles/microservice-testing/

Inside the Box

Unit Testing

Sociable

Solitary

Integration Testing

Component Testing

Component Testing

shims:

inproctester github.com/aharin/inproctester

Plasma github.com/jennifersmith/plasma

Component Testing

Contract TestingPact

github.com/realestate-com-au/pact

Pacto github.com/thoughtworks/pacto

Janus github.com/gga/janus

End-to-End Testing

Test Pyramid for Microservices

engineering

Deployment

Sam Newman

Building MicroservicesDESIGNING FINE-GRAINED SYSTEMS Abstract out underlying

platform dierences to provide a uniform deployment

mechanism.

Dont Let Changes Build Upstaging production

Dont Let Changes Build Upstaging production

Sam Newman


Dont let changes build up - release as soon as you can, and

preferably one at a time!

Integration & Disintegration

Reducing Risk of Release

production

Components are deployed.

Features are released.

Applications consist of routing.

Blue/Green Deployments

Message Router

Web serverApplication

serverDatabase

server

Message Router


serverDatabase

server

1.1 1.1 1.1

Message Router


serverDatabase

server

1.1 1.1 1.1


serverDatabase

server

1.2 1.2 1.2

Message Router

1.1 1.1 1.1

Blue/Green for Services

Deploy

Release

Route

Re-route upon failure

production

How Big?

rele

ase

risk

# services

production

Dis-integrate services that

monitoring shows are no longer used

Sam Newman


Use timeouts, circuit breakers and bulk-heads to avoid

cascading failure.

SUMMARY

denitions


what problem

(Micro)service architectures provide unique benets at the cost of increased (essential)

complexity.

You must be this tall to use microservices

Inverse Conway Maneuver

Build teams that look like the architecture you want

(and it will follow).

Efferent Coupling

efferent

Strive for low efferent coupling for your team.

Continuous DeliveryTeams with low eerent coupling deliver relatively independently

into a common integration pipeline (without fearing breaking

each others builds).

?SPresentation Patterns Neal Ford, Matthew McCullough, Nathaniel Schutta http://presentationpatterns.com

Clojure (inside out) Stuart Halloway, Neal Ford bit.ly/clojureinsideout

Functional Thinking bit.ly/nf_ftvideo

Functional Thinking http://shop.oreilly.com/product/0636920029687.do

Understanding the Basics Neal Ford, Mark Richards http://oreil.ly/1kM7IuV

Taking a Deeper Dive Neal Ford, Mark Richards

http://oreil.ly/RfKUqh

nealford.com@neal4d

building microservice architectures(neal ford)

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