SAA-C03 Design Resilient Architectures Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Configure the Auto Scaling group to span at least three Availability Zones in the same AWS Region.

  Why this is correct

  This is a fundamental best practice for high availability and resilience. By distributing EC2 instances across at least three Availability Zones (AZs), the application can withstand an outage in a single AZ without experiencing downtime. Auto Scaling groups automatically launch new instances in healthy AZs if one fails, ensuring continuous application availability and fault tolerance.

• ✗

  Deploy the Aurora cluster with a single DB instance to reduce complexity and cost.

  Why it's wrong here

  Deploying an Aurora cluster with only a single DB instance, even if it's the primary writer, significantly compromises high availability. If that single instance or its underlying Availability Zone experiences an outage, the database will become unavailable, leading to application downtime. While it might reduce immediate cost, it fails to meet the requirement for a highly available and resilient architecture.

• ✓

  Configure the Aurora cluster to include at least one Aurora Replica in a different Availability Zone than the primary instance.

  Why this is correct

  This configuration is crucial for database resilience and high availability. An Aurora Replica in a different Availability Zone acts as a failover target, allowing Aurora to automatically promote the replica to primary in case of an outage affecting the original primary instance or its AZ. This multi-AZ deployment minimizes downtime and ensures continuous database operations.

• ✓

  Use an Application Load Balancer (ALB) to distribute traffic across EC2 instances in multiple Availability Zones.

  Why this is correct

  An Application Load Balancer (ALB) is essential for distributing incoming application traffic efficiently and for enhancing resilience. By automatically routing requests to healthy EC2 instances across multiple Availability Zones, the ALB ensures that no single instance becomes a bottleneck and that the application remains available even if instances or an entire AZ fail. This provides fault tolerance and improves overall application responsiveness.

• ✗

  Place the EC2 instances in a single Availability Zone to ensure data locality with the primary database.

  Why it's wrong here

  Placing all EC2 instances in a single Availability Zone creates a single point of failure, directly contradicting the goal of a highly available and resilient architecture. While it might offer marginal latency benefits for data locality, the risk of a complete application outage if that specific AZ experiences an issue far outweighs any perceived advantage. High availability mandates distribution across multiple AZs.

• ✓

  Set up an Amazon RDS Proxy to manage database connections and provide connection pooling for improved resilience.

  Why this is correct

  Amazon RDS Proxy enhances application resilience by managing and pooling database connections, reducing the overhead on the database instance. In the event of a database failover, RDS Proxy automatically routes connections to the new primary instance, minimizing application disruption and transparently handling connection management. This improves fault tolerance and application stability during database events.

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