ljc mashup "building java microservices for the cloud && chuck norris doesn't need...

Building Java (micro)services for the CloudThe DHARMA principles

Daniel BryantPrincipal Consultant, Open Credo

daniel.bryant@opencredo.com@danielbryantuk

Chuck Norris Doesn’t Need DevOps…but Java Developers might benefit

Who Am I?

• LJC Associate

• Adopt OpenJDK and JSR

10/11/2014 @danielbryantuk

• Principal Consultant at OpenCredo

Agile transformations

DevOps, Cloud and Microservices

Big Data

The Current Industry Wish List…

• Service-Oriented Architecture

• Cloud-based deployments

• DevOps Culture

@danielbryantuk10/11/2014

The Current Industry Wish List…

• Service-Oriented Architecture– muCon 2014 (coming soon via skillsmatter.com)

• Cloud-based deployments– JavaOne 2014 (coming soon via parleys.com)

• DevOps Culture– Devoxx UK talk (bit.ly/1BylnZb)

– Previous LJC Event (bit.ly/1elVPJz)

So, what’s all this I hear about small services?…

“Microservices”aka

• “SOA done right”

• “SRP” services– “Java, The Unix Way” (bit.ly/1cX8VsS)

• “Small” codebase services – 1000 LOC… 100… 10…?

• “12 Factor apps” (12factor.net)

• My personal opinion…

“Can I fit the service in my head?”

Moving to the Cloud – common problems…

Not respecting the underlying environment

Lack of application/platform monitoring…

Bizarre failure modes…

Difficulty in understandingthe new architecture

Not testing in the Cloud…(hint: here be dragons!)

We’ve created the “Cloud DHARMA Principles” to act as a checklist when building Cloud apps

Documented (just enough)

Highly cohesive/loosely coupled (all the way down)

Automated from commit to Cloud

Resource aware

Monitored thoroughly

Antifragile

Resource aware

Antifragile

API Docs with Swagger

helloreverb.com/developers/swagger

Create a PACT

github.com/DiUS/pact-jvm

Resource aware

Antifragile

High Cohesion / Loose Coupling(all the way down…)

• Code

• Architecture– Components

– Services

• Public API– PayPal (bit.ly/1hnZNly)

Microservices: Architectural Silver Bullet?

• Enforce service boundaries– Bounded contexts

– Domain-Driven Design

• Separation of Concerns– Encapsulate what varies

– Easier to scale/tune independently

• Is this a free-lunch? (bit.ly/1gSw4L7)

No!! It’s all too easy to…

1) Create a distributed monolith

2) Push complexity into orchestration

www.codingthearchitecture.com/2014/07/06/distributed_big_balls_of_mud.html

Sneak-peak: Smashing the Monolith…

• Business functionality -“Cart Service”– Noun, verb, SRP (slidesha.re/1owdJhh)

• Technology chunk - “Email Service”

• Vertical Slice - “Service per page” – Groupon (vimeo.com/105880150)

• Horizontal Slice - “User Repo” – An anti-pattern?

DZone’s Enterprise Integration Guide

www.dzone.com/page/research

Resource aware

Antifragile

Thou Shalt Know thy Cloud…

“Everything fails all the time [in the cloud]”

Werner Vogels, CTO, Amazon.com

• Everything is ephemeral

• Volatility

• Noisy (virtual) neighbours– bit.ly/1w1HQy7

Resource aware

Antifragile

• The opposite of fragile?

– Robust…

– Antifragile…

• Netflix are best-in-class

– bit.ly/1gs5n3q

• System must be robust first!

Design for Failure

• Distributed Computing Principles

– ‘For young bloods’ (bit.ly/1pKVepz)

– Eight Fallacies… (bit.ly/1zCBet7)

• Design patterns

– Timeouts / retries

– Bulkheads / circuit-breakers

Retries

github.com/rholder/guava-retrying

github.com/Netflix/Hystrixprojects.spring.io/spring-cloud/

Circuit-breaker/bulkhead

Antifragile Patterns: Elastic Scaling

Stateless components

Distributed data stores / caches

Resource aware

Antifragile

Microservices in the Cloud…

and now to DevOps…

…or as the recruiters like to say

“DeeVoips”, “DevAnOps” and “Dev-Oops”

What’s in a Name?

• “Development / Operations”

• Increasing cohesion between:– Business

– Development

– Quality Assurance

– Operations

“Bu-Dev-Qa-Ops”?

So, What’s Chuck Norris Doing Here?

Chuck Norris doesn’t need DevOps…

…as a one-man army he codes with one hand, tests with the other and deploys with his beard

The rest of us…

…work in teams to develop software

Software Development Teams

• Developers

• Quality Assurance

• Operations

• Developers

• Operations

• Developers

• Operations

• Developers

• Operations

This silo mentality has to stop

Culture is Vital

• Culture drives behaviour, drives culture…

– “Communication, simplicity, feedback, courage”

– Everyone is responsible for delivery

– Continuous experimentation and learning

• Not easy to change culture

– The hardest part of DevOps…

– …but you will learn new things

Changing Culture

• Create an effective team…

• “Habits of highly effective technical teams”

– Martijn Verburg (bit.ly/1aF9SnK)

• “Patterns of Effective Teams”

– Dan North (vimeo.com/68226771)

Chuck Norris doesn’t do QA…

…Chuck Norris can test an entire application with a single assert

(and get 110% code coverage)

The rest of us…

…need high-quality automated QA

Automating QA

• Intra-component integration testing

– Utilise embedded datastore/middleware

– Cucumber (via ports/adapters/API?)

• Fault-tolerance

– Chris Batey’s Skillscast (bit.ly/1tU6wZj)

– WireMock + Saboteur (wiremock.org)

– “Scassandra” (github.com/scassandra)

Automating QA

• Inter-component integration testing

– The hardest part of SOA…

– Consider ‘synthetic txns’ (active monitoring)

• Service virtualisation

– Mountebank (www.mbtest.org)

– Mock external services (e.g. Spring profiles)

All arrays Chuck Norris creates are of infinite size…

…as Chuck Norris knows no bounds

The rest of us…

…should manage our resources and cultivate ‘mechanical sympathy’

Cultivating “Mechanical Sympathy”

• Virtualisation– Tech Target (bit.ly/1kDVqyG)

• Networking– ‘Unix and Linux System Administration Handbook’

– AWS docs aws.amazon.com/documentation

• Thinking/Acting Operationally– You write it, you run it… (“dev on call”)

When Chuck Norris throws Exceptions…

…everybody knows about it because they land outside of the data center

The rest of us…

…should log all errors (and other vital information for diagnostic purposes)

Monitor All The Things!

• Infrastructure monitoring– Nagios / Zabbix

– Codahale, Actuator

• Distributed Tracing – twitter.github.io/zipkin

• Centralised Logging– logstash.net

The ‘ELK’ Stack

blog.comperiosearch.com/blog/2014/08/14/elk-one-vagrant-box

“…but what should I graph?”

Phrase borrowed from Etsy!

Thanks For Listening

• Massive thanks

– OpenCredo (@OpenCredo)

– notonthehighstreet.com

– RecWorks & The LJC

• Questions / comments?

– daniel.bryant@opencredo.com

– @danielbryantuk

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