Your team runs a tightly coupled distributed workload (for example, synchronous training nodes) across many EC2 instances placed within a single cluster environment. The instances need low-latency networking to reduce delays at synchronization barriers. Which EC2 placement strategy should you use to improve inter-node latency?

Create a placement group with the 'spread' strategy to separate instances across underlying hardware for fault tolerance.

Spread placement groups are designed for high availability by distributing instances across distinct underlying hardware. This does not specifically optimize for low latency between instances, and it may increase network variability for synchronization-heavy workloads.

Use the default placement strategy and rely on Auto Scaling to keep instances from drifting to different locations.

The default strategy does not guarantee physical co-location for low-latency networking. Auto Scaling changes the set of running instances over time and can introduce placement variation, so it cannot reliably eliminate network latency spikes caused by instance placement.

Avoid placement groups and instead use Amazon S3 for inter-node messaging to minimize direct network traffic between instances.

S3 is not designed for low-latency synchronization traffic between tightly coupled nodes. Using S3 introduces object storage semantics and higher request/processing latency compared to direct instance-to-instance networking in a cluster placement group.

What does this SAA-C03 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Create a placement group with the 'cluster' strategy to place instances close together and reduce network latency. — Use a placement group with the 'cluster' strategy. Cluster placement groups aim to place instances close together (within the same Availability Zone) to improve inter-instance network performance—typically higher bandwidth and lower latency. This is the most appropriate placement strategy for synchronization-heavy, tightly coupled workloads where barrier time depends on network latency between nodes. Spread is optimized for fault tolerance rather than low-latency co-location, and the default strategy does not ensure consistent physical proximity. Why others are wrong: Spread prioritizes availability and can increase network variability, which is counterproductive for synchronization barriers. Default placement provides no low-latency placement guarantees and Auto Scaling can exacerbate placement jitter. S3-based messaging changes the communication model to a higher-latency storage workflow rather than improving direct low-latency networking between nodes.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.