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Difficulty: HardHigh-Performing and Elastic Compute Solutions

An advertising technology company is deploying a real-time bidding (RTB) engine on Amazon EC2 instances to process ad auctions. The engine must maintain sub-millisecond node-to-node network latency to synchronize internal state tables across the cluster. The bidding application runs on a custom port, 90809080, on each EC2 instance. The company deploys a Network Load Balancer (NLB) with a listener on port 8080 to receive incoming HTTP requests from external ad exchanges and route them to the EC2 instances. During initial testing, the NLB marks all EC2 instances as unhealthy, and node-to-node communication latency is higher than expected. Which combination of EC2 placement and load balancer target group configuration will resolve these issues while meeting the performance requirements?

  1. A
    Deploy the EC2 instances in a spread placement group. Configure the NLB target group health check to query port 9080.
  2. B
    Deploy the EC2 instances in a cluster placement group. Configure the NLB target group health check to query port 80.
  3. Deploy the EC2 instances in a cluster placement group. Configure the NLB target group health check to query port 9080.Answer
  4. D
    Deploy the EC2 instances in a partition placement group. Configure the NLB target group health check to query port 80.

Answer

Deploy the EC2 instances in a cluster placement group and configure the NLB target group health check to query port 9080.
To achieve sub-millisecond network latency between nodes, the EC2 instances must be deployed in a cluster placement group. Cluster placement groups place instances physically close to each other in a single Availability Zone, which minimizes latency. Additionally, because the application is listening on port 9080, the Network Load Balancer target group health check must be explicitly configured to query port 9080 (or the traffic port routing to 9080) instead of the default port 80 listener, ensuring the load balancer can verify that the service is running.

Step-by-Step Solution

1
Analyze the latency requirement for node-to-node communication.
The system needs sub-millisecond network latency to synchronize state tables between instances.
Cluster placement groups pack instances close together within a single Availability Zone, enabling low-latency, high-throughput network performance.
2
Determine the appropriate target group health check port.
The application is bound to port 9080, while the NLB listens on port 80.
Configuring the health check to target the listener port (port 80) will fail because the instances are not running services on port 80. The health check must query port 9080 directly to verify application availability.

Key Concept

Low-latency network clustering with EC2 Cluster Placement Groups and matching ELB health check ports to application-bound ports.
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High-Performing and Elastic Compute Solutions

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