GANESH SAMARTHYAM
CODEOPS TECHNOLOGIES
A Gentle
Introduction

What is
DevOps?

DevOps is a set of practices intended to
reduce the time between committing a
change to a system and the change being
placed into normal production, while
ensuring high quality.
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015

Checkin to release => it
takes ages!
how many weeks, months, or years?!!

DevOps: Lightning fast!

DevOps - Drivers
Evolution of agile
and lean methods
Need for quicker
releases to realise
business needs
Wider availability of
virtualization &
cloud-based
platforms
Increased
availability of data
centre automation &
configuration
management tools

DEVS ARE FROM VENUS,
OPS ARE FROM MARS
Steven Haines

Dev
Ops

YOU BUILD IT, YOU
RUN IT
Werner Voegls

Cyclic vs. continuous
delivery
Cyclic delivery
of earlier times
continuous delivery
of modern times
weeks/months/years
hours/days!

Agile and DevOps
• Agile focuses on bridging the gap between user
requirements and realising them and testing it. So it
bridges the gap between user requirements and
development + testing.
• DevOps focuses on bridging the gap between the
developers and the operations people. So, in
addition to users functional and non-functional
requirements, devops focuses on operational and
business readiness

DevOps principles
• Systems thinking - looking at how the entire system
works instead of silos (like development teams, IT
operations team, etc)
• Amplify feedback loops
• A culture of continual experimentation and learning

DEVELOP SYSTEMS,
NOT SOFTWARE
Ben Butler Cole

The deployment pipeline
Source: “Continuous Delivery: Reliable Software Releases Through Build, Test, and and Deployment Automation”, Jez Humble, David Farley, Addison Wesley, 2010

DevOps processes
• Treat operators as first class citizens
• Make Dev more responsible for incident handling
• Enforce deployment practices uniformly across
both dev and ops
• Use continuous deployment
• Develop infrastructure code using same processes
as application code
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015

Deployment strategies
• Two basic all of nothing strategies
• Blue/Green (Red/Black) – leave N instances with
version A as they are, allocate and provision N
instances with version B and then switch to version B
and release instances with version A.
• Rolling Upgrade – allocate one instance, provision it
with version B, release one version A instance.
Repeat N times.
• Partial strategies are canary testing and A/B testing.
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015

Blue-green deployments
source: http://martinfowler.com/bliki/BlueGreenDeployment.html

Rolling upgrade
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015

Feature toggles
• Develop version B with new code under control of
feature toggle
• Install each instance of version B with the new code
toggled off.
• When all of the instances of version A have been
replaced with instances of version B, activate new code
through toggling the feature.
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015
Key idea: differentiate between
installing a new version and
activating a new version

Canary testing
• Canaries are a small number of instances of a new
version placed in production in order to perform live
testing in a production environment.
• Canaries are observed closely to determine whether the
new version introduces any logical or performance
problems. If not, roll out new version globally. If so, roll
back canaries.
Source: DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu, Addison-Wesley Professional, 2015

Canary testing
source: http://media.cagle.com/96/2014/05/14/148486_600.jpg
Using birds in coal
mines to detect
leakage of dangerous
gases

A/B testing
Source: http://blog.christianposta.com/images/abtesting.png

Rollback or roll forward?
• When newly deployed feature has bugs or other
problems (e.g., performance), what to do?
• Roll back (undo the deployment)
• Roll forward (replace the feature with new feature /
fixed version)

THE MOST POWERFUL TOOL
WE HAVE AS DEVELOPERS
IS AUTOMATION
Scott Hanselman

Deployment tools
• “Bake” machine images
• “Recipes” for standard configurations
• DevOps engineers manage the recipes
• “Infrastructure as code” approach
• Scripts are managed with similar processes as
source code (e.g., versioned in configuration
management systems)

Server snowflakes
• Server configurations can be different. This makes
reproducing the problem in the production
environment difficult in the production environment.
source: http://www.livescience.com/images/i/000/009/284/original/ig35_snowflakes_13_02.jpg?interpolation=lanczos-none&downsize=660:*

Automated deployment
mechanism: Tools
Shell Scripts
Puppet
Redhat Kickstart
Solaris Jumpstart
Chef
Debian Preseed

Infrastructure configuration
management
Apache
ZooKeeper
Puppet
Noah
Chef
Environment
virtualisation
Vagrant
Xen
VeeWee
KVM
Deployment
automation
Capistrano

DevOps: Challenges
• How to integrate security audits on continually
changing codebases?
• How to run static analysers - they take quite a bit of
time to run and can delay builds?
• How to deal with culture change in the org
(developers and operators - both will resist)

DevOps and related topics
• Continuous integration focuses on integrating code
changes by developers so that the main branch is
up-to-date
• Continuous delivery focuses on taking the results of
continuous integration builds and put them into
production
• DevOps and Cloud technologies are intricately
connected though DevOps practices can be used
independently of the cloud

DevOps benefits
• Quicker delivery - shorter time from need to
realisation
• Better quality
• Increased organisational effectiveness

DEPLOYMENT CELEBRATIONS SHOULD
BE ABOUT THE VALUE OF THE NEW
FEATURES, NOT JOYFUL RELIEF THAT
NOTHING WENT HORRIBLY WRONG
Rebecca Parsons

DEVOPS IS NOT A GOAL, BUT A
NEVER-ENDING PROCESS OF
CONTINUAL IMPROVEMENT
Jez Humble

Recommended
Reading

FROM CONCEPT TO CASH
➤ Lean Software Development
book provides the foundation for
DevOps; its principles are:
➤ Eliminate waste
➤ Amplify learning
➤ Decide as late as possible
➤ Deliver as fast as possible
➤ Empower the team
➤ Build quality in
➤ See the whole
➤ Read it to perform value stream
mapping for DevOps“Implementing Lean Software Development: From Concept to Cash”, Mary
Poppendieck, Tom Poppendieck, Addison-Wesley Professional, 2006
https://amzn.com/0321437381

A BROAD PERSPECTIVE
➤ DevOps is more than bringing
in DevOps engineers or using
tools
➤ This book provides an overall
perspective of DevOps by
covering its history and covers
foundational concepts
➤ Covers four pillars of effective
DevOps: Collaboration,
Affinity, Tools, and Scaling
➤ Has interesting case studies,
clears misconceptions, and
helps troubleshoot
Effective DevOps: Building a Culture of Collaboration, Affinity, and Tooling at
Scale, Jennifer Davis, Katherine Daniels, O'Reilly Media, 2016
https://amzn.com/1491926309

CD DISTILLED
➤ An early book on Continuous
Delivery
➤ Released before DevOps
became a buzzword - but it
covers dev ops concepts in its
essence
➤ Book divided into three parts:
Foundation, The Deployment
Pipeline, and The Delivery
Ecosystem
➤ Written based on the practical
experience of authors and covers
important aspects such as
feature toggles; hence must read“Continuous Delivery: Reliable Software Releases Through Build, Test, and and
Deployment Automation”, Jez Humble, David Farley, Addison Wesley, 2010
http://www.amazon.in/dp/0321601912

WHY DEVOPS?
➤ From the authors of the
popular “The Visible Ops
Handbook”
➤ This book shows why DevOps
and how it helps business win
➤ It tells the story of an IT
manager who has to rescue an
IT project in crisis
➤ Written in a fiction style, so
easy to read
➤ An important read for
managers for effective adoption
of DevOps practices“The Phoenix Project: A Novel About IT, DevOps, and Helping Your Business Win”,
Gene Kim, Kevin Behr, George Spafford, IT Revolution Press, 2013
https://amzn.com/0988262592

ARCHITECT’S PERSPECTIVE
➤ Most books on DevOps talk
about tools, process and
technology perspective
➤ This book is a take on an
architect’s perspective on
DevOps
➤ Covers deployment
pipeline, cross-cutting
concerns (monitoring,
security, …), and case
studies
➤ A bit-dry (written in more of
an academic style)
DevOps: A Software Architect's Perspective, Len Bass, Ingo Weber, Liming Zhu,
Addison-Wesley Professional, 2015
https://amzn.com/0134049845

ganesh@codeops.tech @GSamarthyam
www.codeops.tech slideshare.net/sgganesh
+91 98801 64463 bit.ly/sgganesh

IMAGE CREDITS
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