AWS Certified SysOps Administrator – Associate (legacy) — Question 707

A sysops administrator has an AWS Lambda function that performs maintenance on various AWS resources. This function must be run nightly.
Which is the MOST cost-effective solution?

Answer options

• A. Launch a single t2.nano Amazon EC2 instance and create a Linux cron job to invoke the Lambda function at the same time every night.
• B. Set up an Amazon CloudWatch metrics alarm to invoke the Lambda function at the same time every night.
• C. Schedule an Amazon EventBridge (Amazon CloudWatch Events) rule to invoke the Lambda function at the same time every night.
• D. Implement a Chef recipe in AWS OpsWorks stack to invoke the Lambda function at the same time every night.

Correct answer: C

Explanation

Using an Amazon EventBridge (Amazon CloudWatch Events) rule to trigger the Lambda function is the most cost-effective and serverless solution, as it incurs virtually no cost for simple scheduled events. Options A and D are inefficient because they require running infrastructure (EC2 instances or OpsWorks stacks) continuously, which incurs unnecessary ongoing costs. Option B is incorrect because CloudWatch metric alarms are designed to trigger based on metric thresholds, not on time-based cron schedules.