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Difficulty: HardHigh-Performing and Elastic Compute Solutions

An energy exploration firm runs a distributed seismic data processing application on Amazon EC2 instances. The application performs heavy parallel calculations and requires sub-millisecond node-to-node network latency across all instances to synchronize state. The application is accessed by internal visualization tools on port 7001, and a Network Load Balancer (NLB) is deployed to distribute client requests. The operations team notices that newly launched instances fail health checks and are not receiving traffic. Which configuration will resolve the health check failures and satisfy the low-latency network requirements?

  1. A
    Create the instances inside a spread placement group. Route traffic to port 7001 in the NLB target group, and set the health check port to 7001.
  2. B
    Create the instances inside a cluster placement group. Route traffic to port 7001 in the NLB target group, and set the health check port to the default HTTP port 80.
  3. Create the instances inside a cluster placement group. Route traffic to port 7001 in the NLB target group, and set the health check port to 7001.Answer
  4. D
    Create the instances inside a partition placement group. Route traffic to port 7001 in the NLB target group, and set the health check port to the default HTTP port 80.

Answer

The correct configuration is to create the EC2 instances inside a cluster placement group and configure the NLB target group to route traffic and perform health checks on the application's port, which is port 7001.
The correct configuration launches the instances in a cluster placement group to ensure they are physically close enough to achieve sub-millisecond node-to-node latency, and sets the health check port to port 7001 to match the port on which the seismic application is running, allowing the load balancer to verify instance health successfully.

Step-by-Step Solution

1
Analyze the network latency requirement.
The application requires sub-millisecond node-to-node communication for distributed seismic processing.
EC2 cluster placement groups must be used to locate instances close together on the underlying hardware, providing low-latency and high-throughput network performance.
2
Identify the cause of the load balancer health check failure.
The application is listening on port 7001, but the default health check settings or mismatched port configurations point to a different port.
If the load balancer attempts to check health on a port where no service is running (such as port 80), the checks will fail and instances will be marked unhealthy.
3
Select the correct combination of placement group and port settings.
Combine a cluster placement group with a target group configured to perform health checks on port 7001.
This satisfies both the sub-millisecond latency requirement and ensures the load balancer accurately detects instance health on the correct application port.

Key Concept

Tightly-coupled compute workloads require cluster placement groups for low-latency network communication, and target group health checks must align with the application port to prevent routing failures.
Estimated Time:2m 0s
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High-Performing and Elastic Compute Solutions

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