Questions 43 to 45

Question 43

You have been asked to deploy a new High-Performance Computing (HPC) cluster. You need to create a design for the EC2 instances that ensures close proximity, low latency, and high network throughput.

Which AWS features will help you achieve this requirement while considering cost? (Select TWO)

1. Use Provisioned IOPS EBS volumes.
2. Launch I/O Optimized EC2 instances in one private subnet in an AZ.
3. Use EC2 instances with Enhanced Networking.
4. Use dedicated hosts.
5. Use Placement groups.

Correct Answer: 3, 5

Explanation: When you launch a new EC2 instance, the EC2 service attempts to place the instance in such a way that all of your instances are spread out across underlying hardware to minimize correlated failures. You can use placement groups to influence the placement of a group of interdependent instances to meet the needs of your workload. Depending on the type of workload, you can create a placement group using one of the following placement strategies:

• Cluster packs instances close together inside an Availability Zone. This strategy enables workloads to achieve the low-latency network performance necessary for tightly-coupled node-to-node communication that is typical of HPC applications.
• Partition spreads your instances across logical partitions such that groups of instances in one partition do not share the underlying hardware with groups of instances in different partitions. This strategy is typically used by large distributed and replicated workloads such as Hadoop, Cassandra, and Kafka.
• Spread strictly places a small group of instances across distinct underlying hardware to reduce correlated failures.

Cluster Placement groups are recommended for applications that benefit from low network latency, high network throughput, or both. They are also recommended when the majority of the network traffic is between the instances in the group. To provide the lowest latency and the highest packet-per-second network performance for your placement group, choose an instance type that supports enhanced networking.

INCORRECT: “Use Provisioned IOPS EBS volumes.” is incorrect because provisioned IOPS EBS volumes are geared more towards storage performance than network performance.

INCORRECT “Launch I/O Optimized EC2 instances in one private subnet in an AZ.” is incorrect. I/O optimized instances are also geared more towards storage performance than network performance.

CORRECT: “Use EC2 instances with Enhanced Networking.” is the correct answer.

INCORRECT: “Use dedicated hosts.” is incorrect. Dedicated hosts might ensure close proximity of instances but would not be cost efficient.

CORRECT: “Use Placement groups.” is the correct answer.

References:

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html