Principles Of DevOps

Question 1

Value stream

Answer 1

The sequence of activities required to design, produce and deliver a good or service to the customer, including dual flow of information.

Question 2

Ways to ensure predictable and fast lead times: 4

Answer 2

Using small batch sizes.
Reducing work in process/progress (WIP).
Preventing rework.
Constantly optimizing.

Question 3

What is deployment lead time?

Answer 3

The time from when an engineer checks a change into version control until the change is successfully running in production, providing value to the customer.

Question 4

What are the two measures commonly used in Lean to measure performance in value streams?
And what is the difference?

Answer 4

Lead time and processing time (also known as touch time or task time).
Lead time starts when request is made, ends when request is fullfilled.
Processing time starts when the work has begun, it omits the time that work is waiting either to be processed or in queue.

Question 5

Why do we focus on reducing lead time in DevOps?

Answer 5

Because lead time is what the customer experiences, and achieving fast flow and short lead times requires reducing the time work waits in queues.

Question 6

What does %C/A stand for and what does it measure?

Answer 6

Percent complete and accurate; it measures the quality of the output of each step in the value stream, indicating how often work is usable as is by downstream customers.

Question 7

What is the First Way of the Three Ways in DevOps?
What does it do and how?

Answer 7

The First Way enables fast left-to-right flow of work from Development to Operations to the customer by making work visible, reducing batch sizes, building in quality, and optimizing for global goals.

Question 8

What is the Second Way of the Three Ways in DevOps?

Answer 8

The Second Way enables fast and constant flow of feedback from right to left, preventing problems from happening again, creating quality at the source, and generating or embedding knowledge where needed.

Question 9

What is the Third Way of the Three Ways in DevOps?

Answer 9

The Third Way supports a high-trust culture of experimentation and risk-taking, enabling organizational learning from successes and failures, and multiplying the effects of new knowledge.

Question 10

What are some key practices resulting from the First Way?

Answer 10

Continuous build, integration, test, and deployment processes, creating environments on demand, limiting work in process (WIP), and building systems and organizations that are safe to change.

Question 11

Flow velocity
What is it?
What does it measure?

Answer 11

number of flow items (e.g., work items) that are completed in a set time period. Helps to answer whether value delivery is accelerating.

Question 12

Flow efficiency:

Answer 12

the proportion of flow items actively worked on to the total time that has elapsed. Identifies inefficiencies like long wait times and helps teams see if work upstream is in a wait state or not.

Question 13

Flow time:

Answer 13

a unit of business value pulled by a stakeholder through a product’s value stream (i.e., features, defects, risks, and debts).Helps teams see if time to value is getting shorter.

Question 14

Flow load:

Answer 14

number of active or waiting flow items in a value stream. This is similar to a measure of work in progress (WIP) based on flow items. High flow load leads to inefficiencies and to reduced flow velocity or increased flow time. Helps teams see if demand is outweighing capacity.

Question 15

Flow distribution:

Answer 15

the proportion of each flow item type in a value stream. Each value stream can track and adjust these depending on their needs in order to maximize the business value being delivered.

Question 16

How can we increase the flow in the technology value stream?
3

Answer 16

By making work visible, reducing batch sizes, and building quality in to prevent defects from being passed to downstream work centers.

• making work visible
• reducing batch sizes
• building quality in

Question 17

What method is suggested for making work visible in the technology value stream?

Answer 17

Using visual work boards like kanban boards or sprint planning boards where work is represented on physical or electronic cards.

Question 18

Why is it important to limit Work in Process (WIP) in the technology value stream?

Answer 18

Limiting WIP helps reduce multitasking, making it easier to see problems that prevent the completion of work, and ultimately increases productivity.

Question 19

What are the benefits of performing work in small batch sizes?

Answer 19

Small batch sizes result in less WIP, faster lead times, faster detection of errors, and less rework.

Question 20

How does reducing the number of handoffs in the technology value stream improve flow?

Answer 20

It reduces the amount of time work spends waiting in queue and decreases non–value-added time, thereby increasing flow.

Question 21

What are the “five focusing steps” to reduce lead times and increase throughput?
Constraints

Answer 21

1. Identify the system’s constraint.
2. Decide how to exploit the system’s constraint.
3. Subordinate everything else to the above decisions.
4. Elevate the system’s constraint.
5. If a constraint has been broken, go back to step one.

Question 22

What progression of constraints is typical in DevOps transformations?
4

Answer 22

1. Environment creation
2. Code deployment
3. Test setup and run
4. Overly tight architecture

Question 23

What is flow in the context of DevOps?

Answer 23

Flow in DevOps is the ,
movement of work, tasks, and information throughout the entire software lifecycle.

Question 24

What are the seven major types of manufacturing waste according to Shigeo Shingo?

Answer 24

Inventory, Overproduction, Extra Processing, Transportation, Waiting, Motion, Defects

Question 25

How is the modern interpretation of “waste” different from the traditional view?

Answer 25

The modern view focuses on reducing hardship and drudgery in work, aligning with DevOps ideals, rather than just eliminating waste.

Question 26

What is “Partially Done Work” in the context of software development waste?

Answer 26

Incomplete tasks or work waiting in queue, such as unreviewed requirement documents or pending QA reviews.

Question 27

Define “Extra Processes” in software development.

Answer 27

Non-value-adding work or documentation that increases effort and lead times without benefiting the customer.

Question 28

What is meant by “Extra Features” in software development?
Why are they a waste?

Answer 28

Features that are not needed by the customer, adding complexity and effort to testing and managing functionality.

Question 29

What is “Task Switching” in the context of waste?

Answer 29

Inefficiencies caused by managing multiple projects and dependencies, which add extra effort and time.

Question 30

How does “Waiting” contribute to waste in a value stream?

Answer 30

increases cycle time

Delays between tasks or waiting for resources increase cycle time and prevent timely value delivery to the customer.

Question 31

Describe “Motion” waste.

Answer 31

Effort required to move information or materials, including communication issues and handoffs between work centers.

Question 32

What are “Defects” in the context of waste?

Answer 32

Incorrect, missing, or unclear information, materials, or products that require additional effort to resolve.

Question 33

What is “Nonstandard or Manual Work” according to Damon Edwards?

Answer 33

Reliance on non-standard or manual processes that could be automated, such as non-rebuilding servers or manual test environments.

Question 34

What does “Heroics” refer to in the context of organizational waste?

Answer 34

Unreasonable demands on individuals or teams, like emergency tasks or excessive work tickets, which should be avoided.

Question 35

What is the goal when addressing waste and hardships?

Answer 35

To make waste and hardships visible and systematically alleviate them to achieve fast flow and improve efficiency.

Question 36

What capabilities are required to work safely in a complex system?

Answer 36

• Complex work is managed so that problems in design and operations are revealed.
• Problems are swarmed and solved, resulting in quick construction of new knowledge.
• New local knowledge is exploited globally throughout the organization.
• Leaders create other leaders who continually grow these types of capabilities.

Question 37

What is the main goal when testing design and operating assumptions in a safe system of work?

Answer 37

The goal is to increase information flow from as many areas as possible with as much clarity between cause and effect as possible.

Question 38

How do feedback and feedforward loops contribute to a system of work?

Answer 38

They help reinforce or counteract effects within a system, improving resilience, agility, and the ability to learn and innovate.

Question 39

What is the goal of creating feedback and feedforward loops in the technology value stream?

Answer 39

To have fast feedback at all stages, including Product Management, Development, QA, Infosec, and Operations, and to detect issues immediately.

Question 40

What role does telemetry play in feedback loops?

Answer 40

Telemetry allows for monitoring and measuring system components’ performance in testing and production, detecting issues quickly, and radiating information to the entire value stream.

Question 41

How does feedback contribute to continuous learning and quality improvement in a system of work?

Answer 41

To quality: It helps quickly detect and recover from problems, informs how to prevent recurrence
To learning: promotes organizational learning.

Question 42

List the six types of feedback in software development according to Elisabeth Hendrickson.

Answer 42

Dev Tests
Continuous Integration (CI) and Testing
Exploratory Testing
Acceptance Testing
Stakeholder Feedback
User Feedback

Question 43

What are the fastest and slowest feedback types in the feedback cycle?

Answer 43

The fastest feedback types are local tests and test-driven development at the developer’s station, while the slowest are customer or user feedback at the end of the cycle.

Question 44

What is the main goal of swarming when problems occur in a system?

Answer 44

The goal is to contain problems before they spread, diagnose and resolve them, and build deeper knowledge about managing the system.

Question 45

Swarming is necessary for the following reasons:

Answer 45

*It prevents the problem from progressing downstream, where the cost and effort to repair it increases exponentially and technical debt is allowed to accumulate.
*It prevents the work center from starting new work, which will likely introduce new errors into the system.
*If the problem is not addressed, the work center could potentially have the same problem in the next operation (e.g., fifty-five seconds later), requiring more fixes and work.

Question 46

Why is it important to swarm and fix problems immediately rather than delaying the fix?

Answer 46

Swarming prevents the problem from progressing downstream, which increases repair costs and effort, prevents introducing new errors, and avoids recurring issues.

Question 47

How does swarming benefit learning and problem-solving in complex systems?

Answer 47

Swarming enables learning by preventing loss of critical information and addressing problems while they are still fresh, which helps avoid the complications of reconstructing the problem later.

Question 48

What are the key components needed to implement an effective swarming response in technology value streams?

Answer 48

Creating a culture that makes it safe and encouraged to ask for help, stop all the work and swarm the problem, and establishing processes for immediate problem resolution and feedback.

Question 49

What can be a consequence of not addressing problems immediately in complex systems?

Answer 49

Problems can escalate, leading to increased repair costs, accumulation of technical debt, and potential recurring issues in future operations.

Question 50

What is “technical debt” in software development?

Answer 50

Technical debt is the trade-off made by taking shortcuts or implementing quick fixes that result in future problems or additional work.