DOP-C02 Resilient Cloud Solutions 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.

• ✗

  Place all instances in a single Availability Zone to simplify management.

  Why it's wrong here

  Placing all EC2 instances in a single Availability Zone eliminates zone-level redundancy; if that AZ loses power, network connectivity, or suffers a storage failure, every instance becomes unreachable and any data on EBS volumes is at risk. This configuration is a single point of failure even if the application is load-balanced within that AZ, and it does not mitigate the region-wide outage scenario that a multi-region architecture would address.

• ✗

  Use EC2 Dedicated Hosts to ensure capacity.

  Why it's wrong here

  Dedicated Hosts provide a physical server that is exclusively for your use, which is useful for licensing or compliance constraints, but they are still launched in a specific Availability Zone. If that AZ or Region fails, the host and all its instances go down, and Dedicated Hosts do not automatically fail over or reserve capacity across any other location. They are not a high-availability solution and cannot 'ensure capacity' in the sense of regional disaster recovery.

• ✗

  Increase the minimum size of the Auto Scaling group to 10 instances.

  Why it's wrong here

  Raising the Auto Scaling group minimum to 10 instances simply adds more running copies of the application, all of which remain confined to the same AWS Region (or a set of AZs in that region). A region-wide event—such as an AWS service failure spanning the entire Region—takes down all 10 instances simultaneously, and the ASG cannot launch replacements because there is no viable capacity in that Region. The instance count has no bearing on the ability to survive a Region failure, yet it increases cost and operational overhead.

• ✓

  Deploy the application in a second AWS Region and use Route 53 with failover routing.

  Why this is correct

  Deploying the application in a second AWS Region and using Route 53 failover routing gives you active-passive or active-active DNS-level failover: Route 53 health checks continuously monitor the primary endpoint, and when it is unhealthy, DNS queries are answered with the secondary Region's IP addresses. This directly addresses an entire Region becoming unavailable, as long as the secondary Region has the resources and the data needed to serve traffic. For a critical application, combine this with RDS Cross-Region Read Replicas or Aurora Global Database for proper data durability.

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