Defining Microservices

Defining Microservices
Matt McLarty
DevOps: API Management and Application Development
CA Technologies
VP, API Academy
Session DO3X70E
@MattMcLartyBC
#CAWorld

5 © 2015 CA. ALL RIGHTS RESERVED.@CAWORLD #CAWORLD
Agenda
MICROSERVICES – A BRIEF HISTORY
GOALS
PUTTING IT ALL TOGETHER
PRINCIPLES
MICROSERVICES – A DEFINITION
DEPENDENCIES & PITFALLS
1
2
3
4
5
6

Somebody does
something new, then
shares it
•Amazon, Netflix,
Gilt, SoundCloud…
A pattern emerges,
and so do evangelists
•Martin Fowler,
Adrian Cockroft,
Sam Newman…
The trend goes
mainstream, sects
emerge
•SOA revivalists,
container devotees,
DevOps purists…
A Study in IT Trends
Let’s take a step back…

Enterprise IT Timelines
Organization, Architecture & SDLC
2012-20152008-112004-072000-031996-99
Organization IT city states CIO centralization Efficiency, stability
and cost savings
Mobile and
Shadow IT
Rise of the Chief
Digital Officer
Architecture Web meets the
Enterprise
Rise of SOA SOA Golden Age A New Paradigm APIs everywhere
Lifecycle Waterfall ITIL and CMM Rise of Agile Cloud and CI/CD Decentralization &
DevOps

CI/CD
Cloud
Computing
Web APIs
DevOps
Open Source
Everything
Javascript
Frameworks
GitHub
Containers/
Docker
Microservice
Architecture
Resulting Trends…

• No more fear of changeCI/CD
• Instantaneous provisioningCloud Computing
• Self-serve integrationWeb APIs
• An empathetic, agile cultureDevOps
• Instant pluggable codeOpen Source Everything
• A way to create more developersJavascript Frameworks
• A way to connect all these developersGitHub
• Exact replication of code deploymentsContainers/Docker
• Optimal application style for DevOps…Microservice Architecture
What do these trends bring?

 The architectural realization of DevOps?
 SOA 2.0?
 Single function container-based applications?
OR
 By business value…
Take Two

Microservices Business Value – A Technologist’s View
Technology
heterogeneity
Resilience Scaling
Ease of
deployment
Organizational
alignment
Composability
Optimizing for
replaceability
From “Building Microservices” by Sam Newman

Microservices Business Value – A VC’s View
Agility Efficiency
Resiliency Revenue
From “Innovate or Die: The Rise of Microservices” by Matt Miller

Microservices Business Value – A Combined View
Increased Revenue
Agility
Technology
heterogeneity
Ease of
deployment
Organizational
alignment
Composability
Cost Savings
Efficiency
Resiliency Scaling
Optimizing for
replaceability

Business Value Stories
“We can scale our operation independently, maintain unparalleled system availability, and
introduce new services quickly without the need for massive reconfiguration.”
•Werner Vogels, Amazon (2006) https://queue.acm.org/detail.cfm?id=1142065
“…the next generation [architecture] that we are building will give Netflix a strong foundation to
meet the needs of our massive and growing scale, enabling us to delight our global audience.”
•Netflix (2015) http://techblog.netflix.com/2015/01/netflixs-viewing-data-how-we-know-where.html
“Lessens dependencies between teams - resulting in faster code to production.”
•Adrian Trenaman, Gilt (2015) http://www.infoq.com/news/2015/04/scaling-microservices-gilt
“With the new architecture framework, we were able to reduce our lead time for new features to
something that…was much more acceptable for a company trying to play in the highly competitive
music industry.”
•Phil Calçado, SoundCloud (2015) http://philcalcado.com/2015/09/08/how_we_ended_up_with_microservices.html

Microservices Principles
Modularity
Domain
alignment
Systems
thinking

Modularity
“Modularity … is to a technological
economy what the division of labor is to
a manufacturing one.”
- W. Brian Arthur, The Nature of
Technology

Modularity…
• APIs, containers and cloud
• Heroku’s 12 factors
• Encapsulation: “Smart endpoints and dumb pipes”
(Fowler, Lewis)
In the
technology
• Componentized infrastructure
• Evolvable architecture
• Granular ownership (Newman)
In the
system

But Modularity is not enough on its own…
Fine-grained services

Domains
“The heart of software is its ability to solve
domain-related problems for its user.”
― Eric Evans, Domain-Driven Design:
Tackling Complexity in the Heart of Software

Defining Domains
• “Bounded Contexts”Domain-Driven Design
• Separate models for Query and
Command (state change)
Command Query
Responsibility
Segregation (CQRS)
• Client-focused and iterative
• http://www.christenseninstitute.org/key-concepts/jobs-to-be-done/
“Jobs-to-be-done”

Microservice Boundaries
 The consequence of domain definition, or the driver?
 Defining service boundaries is an art, not a science
 Optimal service boundaries will be fluid over time
 So… Design for evolvability!

Organizational Alignment with Domains
Conway’s Law - http://www.melconway.com/Home/Conways_Law.html
Any organization that designs a system
(defined broadly) will produce a design
whose structure is a copy of the
organization's communication structure.
- Mel Conway

Organizational Alignment with Domains
Illustration from Fowler & Lewis - http://martinfowler.com/articles/microservices.html
vs.

But Domains are part of a System…
Image retrieved from https://upload.wikimedia.org/wikipedia/commons/d/d2/Internet_map_1024.jpg

Systems Thinking
A complex system that works is invariably
found to have evolved from a simple system
that worked. A complex system designed from
scratch never works and cannot be patched up
to make it work. You have to start over with a
working simple system.
- John Gall, Systemantics: How Systems Really
Work and How They Fail

Systems, not Applications
 The “Monolith First” movement
 Complex vs. Complicated
– “A car key is simple. A car is complicated. A car in traffic is complex.” –
From Michael Lewis’ Flash Boys
 Monoliths are complex systems disguised as applications
 Understand that you are not “building an application”…
 …You are likely “changing a system”

Respecting the System
 The Butterfly Effect and the echo chamber
 Focus on the interdependencies between components and
domains
– Interfaces, APIs
 Design for constant change

System Control
 The system cannot be controlled…
– “REST emphasizes evolvability to sustain an
uncontrollable system” – Roy Fielding
 …But it can be monitored and influenced
– Think of public policy influencing financial markets
 Focus on shortening the time between data
collection, analysis and resulting action

An architectural style for building an application
as a network-based system of modular services
organized by business domains in order to
improve the application’s evolvability,
deployability, composability, scalability,
resiliency and replaceability
Take Three

Microservices Dependencies
Cloud
infrastructure
Continuous
delivery
DevOps
culture
System
management
APIs Containers?
Adapted from http://martinfowler.com/bliki/MicroservicePrerequisites.html

Potential Pitfalls with Microservices
Technological myopia
Ignoring the pre-requisites
Ignoring service boundaries
Overlooking the system
Trying to control the system
Boiling the ocean

Putting it all together
•The culmination of the Agile/API/Decentralization movement
Understand where Microservices
fit in the evolution of IT
•Increase agility and efficiency to drive revenue and save costsStay focused on business goals
•Pre-reqs like CI/CD, DevOps and Cloud have standalone value
•Modularity is not enough
Know where the benefits are
coming from
•Defining business domains and service boundaries
•Designing, managing and evolving the system
Don’t ignore the hard problems

Sources
 Sam Newman, “Building Microservices” - http://shop.oreilly.com/product/0636920033158.do
 “The Business Behind Microservices”, Daniel Bryant - https://www.opencredo.com/2015/09/24/the-
business-behind-microservices-webinar-replay/
 Wall Street Journal Blog on Microservices, Matt Miller - http://blogs.wsj.com/cio/2015/10/05/innovate-or-
die-the-rise-of-microservices/
 Fowler and Lewis’ blog post - http://martinfowler.com/articles/microservices.html
 “Seven Microservices Anti-patterns”, Vijay Alagarasan - http://www.infoq.com/articles/seven-uservices-
antipatterns
 Learning CTO blog post - http://thelearningcto.com/2015/04/24/the-hidden-costs-of-paas-microservice-
engineering-innovation/
 “REST in AEM”, Roy Fielding - http://www.slideshare.net/AEMHub2014/rest-in-aem-by-roy-fielding

Q & A

Defining Microservices

More Related Content

What's hot

Similar to Defining Microservices

More from Matt McLarty

Recently uploaded

Defining Microservices