Objective 2.1SAA-C03

2.1 Design scalable and loosely coupled architectures.

Objective 2.1 sits in Design Resilient Architectures, which carries 26% of the Solutions Architect Associate exam. The questions below are original, written from the official objective title above, and each explanation cites the AWS page it rests on.

Objective title verbatim from the official objectives. AWS exam page

A worked example

Shown solved, with the whole explanation open: this is what every question here carries.

Design Resilient ArchitecturesModerate

An order event must reach three teams' services, each consuming at its own pace and none missing events while it is down. What do you build?

Correct.

The concept

Two consumers that must both see the same event cannot share one delivery. A publish channel copies an event to every subscriber, and a buffer in front of each consumer is what lets a slow or absent one catch up.

Why this answer

Publishing once and letting the topic copy the event into a queue for each team gives parallel processing plus a durable landing spot, so a team that is offline finds its work waiting when it returns.

  • AOne queue hands a message to one reader. The three services would race, and each event would be handled once between them rather than three times.
  • Correct. Every service owns a buffer that fills whether or not the service is running.
  • CAn endpoint that is down misses deliveries once the retry policy runs out, and nothing holds the event for it.
  • DSeveral functions on one queue split the work rather than repeat it. That is the shape you pick for throughput.
Read the sourceAWS docs: What is Amazon SNS
Source-cited
snssqsfanoutdecoupling

Now you: objective 2.1 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

Design Resilient ArchitecturesModerate

Jobs take up to eight minutes, and your team sees each message handled by several workers at once. The queue is at defaults. What do you change?

Sample question 2 of 3

Design Resilient ArchitecturesHard

A worker sometimes needs 20 hours per message, and the team extends visibility with a heartbeat. Messages still reappear and are processed twice. What now?

Sample question 3 of 3

Design Resilient ArchitecturesEasy

Payment instructions must be applied once each and in the order the user sent them. Which messaging choice promises that?

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Read the sources

These are the official pages the questions above cite. Reading them is studying the objective from the primary source, which is what the explanations point you toward anyway.

More objectives in Design Resilient Architectures