AWS Certified Solutions Architect Professional SAP-C02 Practice Question

The correct answer is to configure Provisioned Concurrency for the Lambda function. This feature is specifically designed for applications that require predictable, low-latency performance by keeping a specified number of execution environments initialized and ready to respond in double-digit milliseconds. This directly addresses the two main requirements: eliminating cold start latency to meet the sub-100ms SLA during sudden bursts and optimizing costs compared to running a constantly active EC2 fleet.

• Increasing the function's memory allocation does provide more CPU power, which can reduce both cold start duration and execution time. However, it does not eliminate the cold start itself. The first request to an idle function will still experience initialization latency, which could violate the strict SLA. This makes it a helpful optimization but not the primary solution for guaranteed low latency.
• Creating a scheduled Amazon EventBridge rule to invoke the function every few minutes is a technique known as a "pinger" or "warmer". This is an outdated practice that is now considered an anti-pattern. It typically only keeps a single execution environment warm, which is insufficient for handling high-throughput bursts of traffic, and it is less reliable and efficient than Provisioned Concurrency.
• While an Application Load Balancer (ALB) can use a Lambda function as a target, using its health check mechanism to keep the function warm is not a recommended or effective pattern for this use case. ALB health checks are designed to monitor target health and route traffic accordingly, not to manage Lambda execution environments for performance. Provisioned Concurrency is the purpose-built AWS feature for this scenario.