Questions 13 to 15

Question 13

A solutions architect is designing a high-performance computing (HPC) application using Amazon EC2 Linux instances. All EC2 instances need to communicate with each other with low latency and high throughput network performance.

Which EC2 solution best meets these requirements?

1. Launch the EC2 instances in a cluster placement group in one Availability Zone.
2. Launch the EC2 instances in a spread placement group in one Availability Zone.
3. Launch the EC2 instances in an Auto Scaling group in two regions. Place a Network Load Balancer in front of the instances.
4. Launch the EC2 instances in an Auto Scaling group spanning multiple Availability Zones.

Correct Answer: 1

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.

For this scenario, a cluster placement group should be used as this is the best option for providing low-latency network performance for an HPC application.

CORRECT: “Launch the EC2 instances in a cluster placement group in one Availability Zone.” is the correct answer.

INCORRECT: “Launch the EC2 instances in a spread placement group in one Availability Zone.” is incorrect as the spread placement group is used to spread instances across distinct underlying hardware.

INCORRECT: “Launch the EC2 instances in an Auto Scaling group in two regions. Place a Network Load Balancer in front of the instances.” is incorrect as this does not achieve the stated requirement to provide low-latency, high throughput network performance between instances. Also, you cannot use an ELB across regions.

INCORRECT: “Launch the EC2 instances in an Auto Scaling group spanning multiple Availability Zones.” is incorrect as this does not reduce network latency or improve performance.

References:

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