Chapter 2 of 4 · AWS SAA-C03
Design Resilient Architectures
Loose coupling, serverless and containers, load balancing and scaling, high availability, and disaster recovery
- 5topics
- 26 minfast track
- 4diagrams and exhibits
- 26%of the exam
Topics in this chapter
Take them in order, or jump to the one you need.
- 1Loose Coupling with Queues and EventsDecouple application tiers with Amazon SQS, SNS, EventBridge, Kinesis and Amazon MQ, and learn when to choose a queue, a topic…Diagram5 min
- 2Serverless and Microservices on AWSBuild scalable stateless designs with Lambda, API Gateway, Step Functions, Fargate, ECS and EKS, and learn how to choose between…5 min
- 3Load Balancing and Auto ScalingScale horizontally with Elastic Load Balancing and EC2 Auto Scaling, and choose between ALB, NLB and Gateway Load Balancer and…Diagram5 min
- 4High Availability and Fault ToleranceDesign highly available, fault tolerant AWS systems with multiple AZs, RDS Multi AZ, Aurora, Route 53 failover and no single…Diagram6 min
- 5Disaster Recovery StrategiesChoose a disaster recovery strategy from RPO and RTO targets, and compare backup and restore, pilot light, warm standby and multi…Diagram5 min
About this chapter
What this chapter covers
A resilient architecture keeps working when load grows, when a component fails, and when a whole location is lost. The exam asks you to pick services and layouts that meet those goals at a sensible cost.
The chapter follows two outline topics. The first is scalable and loosely coupled design, which covers queues, events, serverless, containers, load balancing and Auto Scaling. The second is high availability and fault tolerance, which covers Multi AZ design, failover and disaster recovery.
How the topics fit together
Loose coupling comes first, because a system made of independent parts is easier to scale and easier to keep running.
- Decoupling lets each part fail and scale on its own.
- Scaling adds capacity with load balancers, Auto Scaling, Lambda or containers.
- High availability spreads each tier across Availability Zones.
- Disaster recovery covers the loss of a Region, using RPO and RTO targets to pick a strategy.
In resilience questions, look for the single point of failure first. The correct answer usually removes it with the managed service that does so with the least effort.
How to use these pages
Each topic page has the same shape, so you can skim for what you need.
- What it is: the idea in plain words.
- How it works: the mechanism, with diagrams and examples.
- What to remember for the exam: the facts to memorise.
- Common mistakes: the classic traps.
- Check yourself: three questions to test your understanding.
Pay special attention to the comparison tables. Many questions ask you to choose between two similar services, such as SQS and SNS, or Multi AZ and read replicas.
Ready for more practice?
The full AWS SAA-C03 question bank has 823 questions, with timed practice exams and an explanation for every answer.
This study guide is independent and is not affiliated with, endorsed by, or sponsored by AWS. Vendor names, certification names and exam codes are trademarks of their respective owners and are used for identification only.