AWS (Amazon Web Services) Certification Practice Exam

How can you ensure high availability for your AWS subnets?

1. By placing all subnets in a single availability zone

2. By using multiple routing protocols

3. By ensuring each subnet is within a different availability zone

4. By integrating NAT Gateways in every subnet

The correct answer is: By ensuring each subnet is within a different availability zone

To ensure high availability for your AWS subnets, placing each subnet in a different availability zone is the most effective strategy. In AWS, an availability zone represents an isolated location within a region, which provides fault isolation. By distributing your subnets across multiple availability zones, you effectively minimize the risk of a single point of failure. If one availability zone experiences issues, your other subnets can continue to operate normally, allowing your applications to remain available and resilient. This strategy is particularly beneficial for applications that require redundancy and disaster recovery capabilities. For example, if you are running a web application, distributing it across multiple availability zones means that if one zone goes down due to power or connectivity issues, traffic can still be routed to the healthy zones. This design aligns with AWS best practices for high availability and fault tolerance. The other approaches, such as placing all subnets in a single availability zone or using multiple routing protocols, do not provide the same level of redundancy. While integrating NAT Gateways can help manage outbound traffic from private subnets, it does not directly contribute to the high availability of subnets themselves. Therefore, ensuring each subnet is allocated to a different availability zone is the optimal choice for achieving high availability in AWS architecture.