Using the Theory of Constraints to Prioritize Cloud Foundry App

Migration

Mark Carlson

CTO, ECS Team

@mdcarlson

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Enterprise IT is under the weather…

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Elapsed times from new idea to features

running at scale in production are too long…

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Layers and layers of heavy processes

give the illusion of safety…

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Aging applications often fail to scale, are

fragile under load and brittle when changed…

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Cloud Foundry is part of the prescription

But...

• We don’t just need a better, more cloud-

friendly app server.

• Without process and culture change, CF

is just another tool in a very long parade

of tools.

Common Stages of Cloud Foundry Adoption

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• Investigation and Proof-of-Concept

• Initial Purchase and Production Pilot Project

• Greenfield – Adoption by Development Teams

for New Applications

• Portfolio Modernization – Adoption by Selected

Teams Across the Larger Portfolio

Typical Application Portfolio Mix

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33%

67%

Rebuild

Virtualize, Tolerate

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Three Terrors of the Application Migration Swamp…

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Terror #1 –

Lightning

Sands of

Indecision

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Terror #2 –

Flaming Out

by Forgetting

the Main Goal

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Terror #3

AMOUS’s =

Application

Migrations of

Unusual Size

Choosing apps to migrate?

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“I can clearly not choose the app that is in front of me!” --Vizzini

Don’t Migrate Everything!

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• Applications to Exclude:

• Packaged or SaaS applications

• Apps with tight coupling to hardware or legacy

OS

• Apps with no business reason to change

frequently

• Apps with tenuous connection to consumers or

clear business value

• Apps so trivial… no one will care

• Apps so massive… no one should dare

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Application Migration Factories?

Booo! Booo!

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Theory of Constraints

An overall management philosophy

introduced by Dr. Eliyahu Goldratt

Source: Institute of Management Accountants, “Theory of Constraints (TOC) Management System Fundamentals”, 1999

Bottleneck

(2/hr)

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What is an Innovation Bottleneck?

The inability to rapidly and continuously deliver

business-impacting changes to an app that is an

innovation generator is an…

Innovation bottleneck

• In manufacturing, a constraint is a process, process step,

or anything that limits throughput and prevents the entire

system from achieving its goal.

• A bottleneck is a constraint in a production flow process.

The process step that limits overall capacity.

18 “I've just sucked one year of your life away.” –Count Rugen

Innovation Bottlenecks Suck IT’s Life Away

The initial filters:

• Technical fit 12-factor-ness.

• Size / Complexity

• Directly connected to easily measured business value

• Supporting team not “frozen middle” or “permafrost”

• Eager to embrace new ways and learn new techniques to get better

• Team members are respected. Others will want to follow their lead

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Finding Innovation Bottlenecks

You might have an innovation bottleneck IF:

• The organization’s ability to innovate as a whole is constrained by slow delivery cycles in this application

• The business is pursuing or evaluating a non-traditional provider or public cloud strategy for this application because it can’t be easily changed

• Introducing the smallest feature or change takes weeks or months EVEN when those features will have a major impact on business operations

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Strangle the Bottlenecks

Strangler Application, Martin Fowler, 2004 http://martinfowler.com/bliki/StranglerApplication.html

Strangler Application Migration:

• Avoids big bang

• Intercepts and redirects calls to

new service running on CF

• Wrapped in tests and circuit

breakers

• Each “slice” is connected to

business value that is easily

visible

• Over time, all that remains is a

well understood core that can

be tolerated or eliminated

Don’t let (a little success) go to your head…

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For Further Research

• “Working Effectively with Legacy Code”,

Michael Feathers, 2004

• “The Goal: A Process of Ongoing

Improvement”, Goldratt and Cox, 1984

• “Application Migration Selection Criteria”, Josh

Kruck and Abby Kearns, 2015

• “Migrating the Monolith”, Rohit Kelapure,

SpringOne2Gx 2015

• ”The Cloud Native Journey”, Michael Coté,

2015

• “The Princess Bride”, William Goldman, 1973

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Thank you!

Mark Carlson

@mdcarlson

ECS Team

@ecsteam

http://www.ecsteam.com