Self-test

Question 1

14. (Event-Driven Architecture Style) For better workflow control, would you use the mediator or broker topology?

Answer 1

Mediator

Question 2

4. Which architecture characteristic is more important to strive for—availability or performance?

Answer 2

Depends on how far you are from ideal point in those (which you measure together with business stakeholders). Never shoot for the best architecture, but rather the least worst architecture.

Question 3

23. What can you derive from a business stakeholder telling you “I needed it yesterday”?

Answer 3

That is an indication to the software architect that time to market is important to that stakeholder.

Question 4

21. What is irrational artifact attachment, and why is it significant with respect to documenting and diagramming architecture?

Answer 4

It is the proportional relationship between a person’s irrational attachment to some artifact and how long it took to produce. If an architect creates a beautiful diagram using some tool like Visio that takes two hours, they have an irrational attachment to that artifact that’s roughly proportional to the amount of time invested, which also means they will be more attached to a four-hour diagram than a two-hour one.

Question 5

22. What are three warning signs you can look at to determine if your team is getting too big? (at least one)

Answer 5

• Process loss (One indication of process loss is frequent merge conflicts when pushing code to a repository)
• Pluralistic ignorance (Pluralistic ignorance is when everyone agrees to (but privately rejects) a norm because they think they are missing something obvious.)
• Diffusion of responsibility (Confusion about who is responsible for what on the team and things getting dropped are good signs of a team that is too large.)

Question 6

5. What is the difference between scalability and elasticity?

Answer 6

Scalability is about gradual increase of the load (over time when more and more users are in the system). Elasticity is about spikes of load (Black friday)

Question 7

6. Provide an example of an architecture fitness function to measure the scalability of an architecture.

Answer 7

Max number of requests per minute the system can respond to

Question 8

7. Assume a system consisting of a single user interface with four independently deployed services, each containing its own separate database. Would this system have a single quantum or four quanta? Why?

Answer 8

This depends on how the UI connects to the backend services. If they use microfrontend then the UI could live without one or more of the services (e.g. UI is a webshop andone of the services provides a recommendation service which isn’t critical). On the other hand some of them might be required for the frontend to work (e.g. the catalog service).

Question 9

9. List the eight fallacies of distributed computing. (Name at least 3)

Answer 9

1. The Network Is Reliable
2. Latency Is Zero
3. Bandwidth Is Infinite
4. The Network Is Secure
5. The Topology Never Changes
6. There Is Only One Administrator
7. Transport Cost Is Zero
8. The Network Is Homogeneous

Question 10

1. What is the First Law of Software Architecture?

Answer 10

Everything is a tradeoff

Question 11

24. What is the 20-minute rule, and when is it best to apply it?

Answer 11

Spend 20 minutes daily learning new techs. Better at the morning

Question 12

3. Which is preferred within a code base—static or dynamic connascence?

Answer 12

Static is preferrred because it’s easier to refactor

Question 13

11. Can pipes be bidirectional in a pipeline architecture?

Answer 13

No. Each pipe is typically unidirectional and point-to-point. Remember that this is mostly used for ETL

Question 14

10. What is the architecture sinkhole anti-pattern?

Answer 14

This anti-pattern occurs when requests move from layer to layer as simple pass-through processing with no business logic performed within each layer.

Question 15

8. What is the difference between technical partitioning and domain partitioning? Provide an example of each.

Question 16

2. List the three levels of knowledge in the knowledge triangle and provide an example of each.

Answer 16

Known knowns, Known unknowns, Unknown unknowns

Question 17

17. What is a saga in microservices?

Answer 17

A pattern to update/call multiple service

Question 18

12. What would you do if you had a third-party plug-in that didn’t conform to the standard plug-in contract in the core system?

Answer 18

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Question 19

20. What risk rating (1-9) would you assign to unproven or unknown technologies?

Answer 19

9 (highest)

Question 20

15. What is the difference between a replicated cache and a distributed cache? Which one is typically used in space-based architecture?

Answer 20

The goal of the architecture is to minimize the read-writes from the db. Space-based architecture mostly relies on replicated caching, although distributed caching can be used as well.

Question 21

22. List three basic checklists that would be good for a development team. (At least one)

Answer 21

• Developer code completion checklist (DoD)
• Unit and functional testing checklist (edge-cases test)
• Software release checklist (prevent human-error)

Question 22

13. What technique can you use to manage database changes within a service-based architecture?

Answer 22

Database mirroring

Question 23

19. What are three basic criteria in which you would mark the status of an ADR as Proposed?

Answer 23

Proposed means it needs to be approved by someone (stakeholders, other architects etc.). So the 3 criteria are:

Cost, cross-team impact, and security.

E.g. If the cost of the architecture decision exceeds a certain amount, then it must be set to Proposed status and approved by someone else.

Question 24

16. Is service-oriented architecture technically partitioned or domain partitioned?

Answer 24

Domain