Question

A SysOps administrator configures a CloudWatch alarm on the CPUUtilization metric for a production EC2 instance. The alarm is set to trigger when the average CPU exceeds 80% for 1 consecutive period of 1 minute. However, the alarm consistently reports INSUFFICIENT_DATA even during periods of high CPU load. The instance uses default monitoring settings. What is the MOST likely cause and correct resolution?

Accepted Answer

The instance is using basic monitoring, which publishes metrics every 5 minutes; enable detailed monitoring to receive 1-minute metric granularity.

Answer

The CloudWatch agent is not installed; install and configure the agent to publish the CPUUtilization metric at 1-minute intervals.

Answer

The alarm period must always match the metric namespace retention; change the alarm period to 15 minutes to align with EC2 data retention.

Answer

CloudWatch does not support 1-minute alarms for EC2; recreate the alarm using anomaly detection instead of a static threshold.