Q40 — AWS SOA-C02 Ch.1

Question 40 of 100 | ← Chapter 1

A SysOps administrator must create a solution that automatically shuts down any Amazon EC2 instances that have less than 10% average CPU utilization for 60 minutes or more. Which solution will meet this requirement in the MOST operationally efficient manner?

• A. Implement a cron job on each EC2 instance to run once every 60 minutes and calculate the current CPU utilization. Initiate an instance shutdown if CPU utilization is less than 10%.
• B. Implement an Amazon CloudWatch alarm for each EC2 instance to monitor average CPU utilization. Set the period at 1 hour, and set the threshold at 10%. Configure an EC2 action on the alarm to stop the instance. ✓
• C. Install the unified Amazon CloudWatch agent on each EC2 instance, and enable the Basic level predefined metric set. Log CPU utilization every 60 minutes, and initiate an instance shutdown if CPU utilization is less than 10%.
• D. Use AWS Systems Manager Run Command to get CPU utilization from each EC2 instance every 60 minutes. Initiate an instance shutdown if CPU utilization is less than 10%.

Correct Answer: B. Implement an Amazon CloudWatch alarm for each EC2 instance to monitor average CPU utilization. Set the period at 1 hour, and set the threshold at 10%. Configure an EC2 action on the alarm to stop the instance.

Explanation

该题考查AWS资源监控与自动化管理核心机制。Amazon CloudWatch提供内置的基础监控指标（如CPU利用率），无需安装代理即可直接设置警报，通过设定统计周期（1小时）、阈值（低于10%）和触发动作（停止实例），能够精准实现持续低负载实例自动回收。其他选项或依赖实例内脚本维护（A、C）、或需额外代理配置（C）、或采用轮询方式效率低下（D），均不具备原生告警系统的事件驱动特性与集中管理优势。