A fleet of Linux web servers reports only CPU and network numbers to CloudWatch by default. The team now needs memory consumption and root volume fullness graphed alongside those. What should they deploy?
Show answer and explanation
Answer: D
Memory and disk usage are measured inside the guest operating system, which the hypervisor cannot observe. The unified CloudWatch agent runs on the instance, reads these values, and publishes them to CloudWatch, typically in the CWAgent namespace, where they can be graphed and alarmed on like any other metric. Detailed monitoring only changes the granularity of the hypervisor metrics.
Why the other options are wrong
- A. Detailed monitoring increases the granularity of the standard hypervisor metrics to one minute. It still omits memory and disk usage because those values are not visible outside the guest operating system.
- B. Granting PutMetricData permission lets something publish metrics, but nothing on the instance is collecting memory or disk values yet. Without an agent to gather them, the permission alone gives the team no data.
- C. CloudTrail Insights detects unusual API call patterns in account activity. It does not measure host resource consumption, so it cannot supply memory or disk graphs.