Understand CloudWatch Alarm INSUFFICIENT_DATA State and Its Causes
Network Topology
Refer to the exhibit. The alarm has been in INSUFFICIENT_DATA state for several hours. What is the most likely cause?
Quick Answer
The answer is a stopped or terminated EC2 instance. When an instance is no longer running, CloudWatch stops receiving metric data points, causing the alarm to remain in INSUFFICIENT_DATA state for hours rather than briefly during initial metric collection. This occurs because both the default CPU utilization metric published by AWS and any custom metrics from the CloudWatch agent cease entirely when the instance is shut down or deleted. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding that INSUFFICIENT_DATA is not an error but a signal that no data exists for the evaluation period—a common trap is confusing it with ALARM state or assuming a temporary network blip. Remember the memory tip: “No instance, no data, INSUFFICIENT forever.”
⚠ Common exam trap
Watch out — candidates often confuse INSUFFICIENT_DATA with ALARM or OK states, mistakenly thinking low CPU utilization or missing CloudWatch agent would cause this state, when in fact INSUFFICIENT_DATA strictly means no metric data has been received at all for the evaluation period.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The EC2 instance is stopped or terminated.
The INSUFFICIENT_DATA state for several hours indicates that CloudWatch has not received any metric data points for the specified period. If the EC2 instance is stopped or terminated, the CloudWatch agent stops sending metrics, and the default CPU utilization metric (which is published by AWS, not the agent) also ceases because the instance is no longer running. This causes the alarm to remain in INSUFFICIENT_DATA indefinitely until the instance is started again or the metric resumes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The alarm evaluation period is too long.
Why it's wrong here
Period of 300 seconds is standard; INSUFFICIENT_DATA means no data at all.
- ✓
The EC2 instance is stopped or terminated.
Why this is correct
If the instance is stopped, no metrics are emitted.
- ✗
The instance has no CloudWatch agent installed.
Why it's wrong here
CPUUtilization is a standard metric, no agent needed.
- ✗
The instance is running but the CPU utilization is below the threshold.
Why it's wrong here
If below threshold, the state would be OK, not INSUFFICIENT_DATA.
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Same concept, more angles
1 more way this is tested on SOA-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company has a CloudWatch alarm that monitors the CPU utilization of an EC2 instance. The alarm is set to trigger when CPU utilization exceeds 80% for 5 consecutive minutes. The alarm state is 'INSUFFICIENT_DATA'. What does this mean?
hard- A.The CPU utilization is below 80% for 5 minutes.
- B.The CPU utilization has exceeded 80% for 5 minutes.
- ✓ C.The alarm does not have enough data to determine the state.
- D.The alarm is missing data points for the past 5 minutes.
Why C: The INSUFFICIENT_DATA state in CloudWatch indicates that the alarm has not received enough metric data points to evaluate whether the threshold (CPU utilization > 80% for 5 consecutive minutes) has been breached. This typically occurs when the EC2 instance is newly launched, the CloudWatch agent is not reporting, or there are gaps in metric collection due to network issues or instance stops. It does not imply any conclusion about the CPU utilization level itself.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.