DOP-C02 Monitoring and Logging Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Create a custom CloudWatch metric namespace and publish memory data using the AWS CLI.

  Why it's wrong here

  While the AWS CLI's put-metric-data command can publish arbitrary custom metrics, it does not automatically collect memory data from EC2 instances. You would have to script the memory read on each instance, schedule it via cron, manage IAM credentials, and handle API failures—making it impractical compared to the CloudWatch agent, which is purpose-built for in-guest OS metric collection and publication.

• ✓

  Install the Amazon CloudWatch agent on the EC2 instances to collect memory metrics and publish them to CloudWatch.

  Why this is correct

  The Amazon CloudWatch agent runs inside the guest OS and collects memory metrics such as mem_used_percent, mem_available, and mem_total, publishing them as custom metrics under the CWAgent namespace. It uses an IAM role for secure PutMetricData calls, can be configured via JSON, and can be centrally managed with AWS Systems Manager, making it the standard solution for OS-level metric collection.

• ✗

  Enable detailed monitoring on the EC2 instances to collect memory metrics.

  Why it's wrong here

  Detailed monitoring only changes the interval of AWS-collected EC2 metrics from 5 minutes to 1 minute. These metrics are collected by the hypervisor and include CPU, network, and disk I/O, but never memory because the hypervisor has no visibility into guest OS memory usage. Memory metrics require a guest-side component like the CloudWatch agent.

• ✗

  Use AWS CloudTrail to capture memory utilization events from the EC2 instances.

  Why it's wrong here

  AWS CloudTrail records API calls made to AWS services, such as EC2 RunInstances or StopInstances, for audit and governance purposes. It has no mechanism to capture guest OS performance counters like memory utilization, nor does it sample or stream any operating-system-level data; it is for operational auditing, not metric collection.

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