Finding bottlenecks in our software delivery processes is often pretty easy. But once we squash one bottleneck, another team becomes the limiting factor. This presentation looks how bottlenecks work, and how to predict the next bottleneck you'll need to work on.

1. Pushing the bottleneck
Predicting what will break next in your SDLC

2. Lead Consultant & Tech Evangelist
Eric is Lead Consultant at IBM
UrbanCode Products where I help
customers get the most out of their
build, deploy and release processes.
Today he works with customers and
industry leaders to figure out this
DevOps thing.
Eric Minick
eminick@us.ibm.com
@EricMinick

3. The plan
 Theory of constraints in a nutshell
 Finding bottlenecks
 Predicting the next bottleneck
 Common bottleneck pushing patterns
 Q&A

4. Theory of constraints
in a nutshell

5. A bottleneck is a constraint
Maximum
pouring speed

6. Only by increasing flow through the constraint
can overall throughput be increased*
Making the bottle
wide down here does
not help
* The Goal: a process of ongoing improvement. Goldratt eta al

7. Optimize at your constraint
Can pour faster now

8. Your system must have a measureable goal
My goal is to empty a
wine bottle quickly

9. Simplified five step plan
1. Identify the system’s most severe constraint
2. Decide how to get the most out of the constraint
3. Subordinate everything else to the above constraint
4. Make changes to expand constraint’s capacity
5. Once constraint is relieved, return to step 1

10. Example: Slow QA cycles
1. Identify the system’s most
severe constraint
2. Decide how to get the most
out of the constraint
3. Subordinate everything else
to the above constraint
4. Make changes to expand
constraint’s capacity
5. Once constraint is relieved,
return to step 1
1. It takes too long to test our
changes. Everyone else waits
2. Testers should focus on
exploratory testing
3. Devs help with regression
tests. Ops prioritizes QA.
4. Dev & QA work together to
automate regression tests
5. Find the next bottleneck

11. Wait, what’s our goal in software?
 Generally: turn ideas into business
value
 Measuring “business value” hard
Emptying wine bottles only relevant if dev speed is the constraint
and you believe in the Ballmer Peak (http://xkcd.com/323/)
?

12. Wait, what’s our goal in software?
 Generally: turn ideas into business
value
 Measuring “business value” hard
 Features delivered minus bugs is a
decent approximation
– …but rewards building useless features.
Emptying wine bottles only relevant if dev speed is the constraint
and you believe in the Ballmer Peak (http://xkcd.com/323/)
?

13. Three key measures
 Lag time: how long from idea to value?
 Throughput: how much delivered value
per unit time?
 Cost: what does it cost to deliver value?
?

14. Finding the bottlenecks

15. Most teams can feel the constraint
 What are you waiting on?
 Where’s the pain?
Constraints before you in a
process feel like not enough
work.
Constraints after you in a
process are annoying or
painful

16. If it hurts, do it more often
 Painful processes often grow
exponentially worse with large
batch sizes.
 Examples
– Integration work
– Releases
– Bug Triage
– Updating databases
– Visiting the dentist
http://martinfowler.com/bliki/FrequencyReducesDifficulty.html
Time between doing it
Pain

17. Use Lean techniques to measure
 What does it take to get a change from idea to production?
–At each phase measure wait time and work time
 Long wait times indicate large batch sizes or backlogs
image credits: http://commons.wikimedia.org/wiki/File:Diagram_spaghetti_kilka_produktow.PNG
http://www.michaelnygard.com/blog/2008/02/outrunning_your_headlights.html

18. Manual fix & verify spaghetti

19. Bug fix & verify value stream
720
3600
240
2880
720
3600
240
15
15
120
60
15
15
60
Waiting Working
12000 300
1. Feature build
2. Build deployed
3. Bug reported
4. Dev fixes
5. Fix built
6. Fix deployed
7. Tester verifies

20. Seeing the “next” bottleneck

21. QA Scenario
Dev
Produces a
nightly build
Twice weekly,
2 hour deploy
to Test Lab
3 Days to test
each drop

22. Dev
produces a
nightly build
Twice weekly,
2 hour deploy
to Test Lab
1.5 Days to test
each drop
If we improve test speed, our constraint moves.

23. Examining a constraint
• Manual process
• Limited staff
• Production releases have priority
Why can we only deploy twice a
week to QA?

24. Tackling the constraint
• Manual process
• Limited staff
• Production releases have priority
Why can we only deploy twice a
week to QA?
• Automate processes
• Hire more staff
• Prioritize QA Releases
Options

25. Imagine a 1 day test cycle
Dev
produces a
nightly build
2 hour
deploy to
Test Lab
1.0 Days to
test each
drop
¼ day deploy downtime becomes turns 1 day test cycle into
two days.

26. Tackling the constraint
• Manual process
• Limited staff
• Production releases have priority
Why can we only deploy twice a
week to QA?
• Automate processes
• Hire more staff
• Prioritize QA deploys
Options
Short term approach
Long term approach

27. Measuring utilization helps with this prediction
 “Feeling” the pain isn’t enough to predict the next constraint
 There may be no pain at the next constraint today

28. When something is free, it is used more
 Example: Amazon Prime. For $79/yr, customers get free 2
day shipping on everything.
“…Customers spent as much as 150% more at
Amazon after they became Prime members.
Subscribers not only ordered more often … they
started buying things at Amazon that they
probably wouldn’t have in the past” *
* http://business.time.com/2013/03/18/amazon-prime-bigger-more-powerful-more-profitable-than-
anyone-imagined/

29. Consider implications of making something free
If builds, deploy, regression tests are free…
We’re going to be
testing lots more.
Better buy some
hardware.

30. Common “next bottleneck” patterns

31. After build, deploy is next
 Build guy & deploy guy
used to be in sync
 A CI server can do
hundreds of builds per day
 Agile tends to make
Operations a constraint
Knowing my stuff
compiles at all times is
great. I want to know if
it passes functional
tests too.

32. As tests shift left, expensive tests constrain
 Developers run more integration tests
 Some tests use expensive resources
–pay per use web services, mainframes, production systems…
 Stubbing those resources becomes important
– known as “service virtualization”

33. Concurrent agile dev requires more test labs
 More code is compiling, and set to be released “soon”
 Need more environments to test changes in
– Pressure for Platform as a Service

34. Frequent releases demand fast feedback
 Frequent releases enable experimentation
 Monitoring of business outcomes required
 Architectural pressures to support A/B testing
♫
Stop ignoring difference
between features delivered
and value delivered

35. If we keep chasing constraints,
where does it end?

36. You may end up with Continuous Deployment
Build
Run thousands of tests
Deploy to some servers
Monitor
Deploy to remaining
servers

37. Summary
 Optimizations other than at the constraint don’t help
 “Breaking” one constraint will expose the next
 Patterns or analysis can be used to predict next constraint
 Continual Improvement, Continual Improvement, Continual
Improvement, Continual Improvement…

38. IBM will collaborate with you to
understand your current situation,
goals and constraints. The
Assessment and Planning
Workshop will aim to capture
sufficient information to make
specific recommendations for
improvement and implementation.
 Intended Audience:
Key leadership from practice areas and
stakeholder organizations
 Value Proposition
Clear recommendations for capability
improvements aligned to your business goals
Initial Architecture
Adoption roadmap based on proven best
practices
 Activities
Workshop planning
Assessment and Planning Workshop
Collaborative discussion on current status, future
goals and adoption requirements
Produce Deliverable
 Deliverables
Current Status and Improvement
Recommendations
Architecture
Adoption Roadmap
Assessment and Planning Workshop

39. More resources
Urbancode.com/resources
Continuous Delivery Maturity Model
Deployment Automation Basics
Applying Lean Principals to Software Delivery
Blogs.urbancode.com
Twitter.com/UrbanCode
Facebook.com/IBMUrbanCodeProducts
SlideShare.net/Urbancode

40. 40
SlideShare.net/Urbancode
@EricMinick