Q7 — AWS SOA-C02 Ch.1

Question 7 of 100 | ← Chapter 1

A SysOps administrator wants to monitor the free disk space that is available on a set of Amazon EC2 instances that have Amazon Elastic Block Store (Amazon EBS) volumes attached. The SysOps administrator wants to receive a notification when the used disk space of the EBS volumes exceeds a threshold value, but only when the DiskReadOps metric also exceeds a threshold value. The SysOps administrator has set up an Amazon Simple Notification Service (Amazon SNS) topic. How can the SysOps administrator receive notification only when both metrics exceed their threshold values?

• A. Install the Amazon CloudWatch agent on the EC2 instances. Create a metric alarm for the disk space and a metric alarm for the DiskReadOps metric. Create a composite alarm that includes the two metric alarms to publish a notification to the SNS topic. ✓
• B. Install the Amazon CloudWatch agent on the EC2 instances. Create a metric alarm for the disk space and a metric alarm for the DiskReadOps metric. Configure each alarm to publish a notification to the SNS topic.
• C. Create a metric alarm for the EBSByteBalance% metric and a metric alarm for the DiskReadOps metric. Create a composite alarm that includes the two metric alarms to publish a notification to the SNS topic.
• D. Configure detailed monitoring for the EC2 instances. Create a metric alarm for the disk space and a metric alarm for the DiskReadOps metric. Create a composite alarm that includes the two metric alarms to publish a notification to the SNS topic.

Correct Answer: A. Install the Amazon CloudWatch agent on the EC2 instances. Create a metric alarm for the disk space and a metric alarm for the DiskReadOps metric. Create a composite alarm that includes the two metric alarms to publish a notification to the SNS topic.

Explanation

Amazon CloudWatch监控自定义指标需通过安装CloudWatch代理收集EC2实例的磁盘空间数据。复合警报（Composite Alarm）允许将多个指标警报组合，仅在所有关联警报处于ALARM状态时触发动作。选项A正确使用复合警报同时满足磁盘空间和DiskReadOps阈值；选项B未关联两个条件，会各自触发；选项C中EBSByteBalance%不涉及磁盘使用率；选项D的详细监控无法获取磁盘使用数据。