Question 27
Domain 3: Design High-Performing ArchitecturesAn EC2 instance needs low-latency, high-throughput connectivity to other instances in the same cluster. Which placement group should be used?
Correct answer: A
Explanation
A Cluster Placement Group is used when instances need "low-latency, high-throughput connectivity" because it places them close together in the same Availability Zone. This design minimizes network distance between instances, which is ideal for tightly coupled workloads in the same cluster.
Why each option is right or wrong
A. Cluster Placement Group
AWS EC2 placement groups are defined in the EC2 User Guide: a Cluster placement group packs instances close together within a single Availability Zone to provide the lowest network latency and highest packet-per-second performance. That physical co-location is what the question’s cluster workload needs; Spread placement groups are for fault isolation across distinct hardware, and Partition placement groups are for large distributed systems, not maximum inter-instance bandwidth.
B. Spread Placement Group
C. Partition Placement Group
D. No placement group needed