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Navigating Resilient Architecture Decisions for SAA-C03
Understand a key exam question on resilient architecture. Learn why the right AWS service combination is crucial for application availability.
A common pitfall for candidates is understanding the nuances of resilient architecture. This question tests your knowledge of how to maintain application availability during an Availability Zone failure.
The question
A financial services company requires a resilient architecture for their web application. They want to ensure their application can withstand the failure of an entire Availability Zone. Which AWS service combination should they implement to achieve this?
- A. Amazon S3 and Amazon CloudFront
- B. Amazon RDS with Multi-AZ deployment and EC2 instances across multiple AZs
- C. AWS Lambda and Amazon DynamoDB
- D. Amazon Route 53 and Amazon VPC Peering
Think before you scroll
Before selecting an option, consider the requirements for resilience in terms of both database and application layers. The goal is to ensure that failure in one Availability Zone does not affect the overall application performance.
The answer
The correct option is B: Amazon RDS with Multi-AZ deployment and EC2 instances across multiple AZs. This combination ensures that both the database and the application can failover seamlessly. RDS Multi-AZ provides automatic failover capabilities, while deploying EC2 instances in multiple AZs adds additional resilience to the application layer.
Why the other options lose
- A: Amazon S3 and Amazon CloudFront: While these services help with content delivery and storage, they do not address application-level resilience or database failover strategies. They cannot maintain application availability during an AZ failure.
- C: AWS Lambda and Amazon DynamoDB: This combination offers high availability but does not provide the necessary failover for applications hosted on EC2. Lambda and DynamoDB do not inherently ensure that the application can withstand an entire AZ failure.
- D: Amazon Route 53 and Amazon VPC Peering: Route 53 is primarily for DNS management and does not provide architecture-level resilience. VPC Peering facilitates communication between VPCs but does not address the need for resilience against AZ failures.
The concept behind it
To design a resilient architecture, you should always consider redundancy at both the application and database layers. Multi-AZ deployments for databases ensure automatic failover, while distributing application servers across multiple AZs prevents a single point of failure.
Exam trap to remember
Always remember: redundancy is key to resilience. Ensure that both application and database layers are designed to handle failures across Availability Zones.