DOP-C02 Incident and Event Response Practice Question
A DevOps engineer receives an alarm that an EC2 instance's CPU utilization has exceeded 90% for 5 minutes. The engineer needs to automatically recover the instance. Which AWS service should be used to configure automatic recovery?
⚠ Common exam trap
It's easy for candidates to confuse EC2 Auto Scaling (which replaces instances) with automatic recovery (which recovers the same instance), or they overcomplicate the solution by choosing Lambda or Systems Manager when a simple CloudWatch Alarm action is the correct and native AWS mechanism.
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
✓
Amazon CloudWatch Alarms
Amazon CloudWatch Alarms can be configured to trigger an EC2 instance recovery action when a metric like CPU utilization exceeds a threshold (e.g., 90% for 5 minutes). The alarm sends a signal to the EC2 service, which automatically recovers the instance by stopping it and starting it on a new underlying host, preserving the instance ID, private IP, and Elastic IP. This is the native, built-in mechanism for automatic instance recovery without requiring additional compute or orchestration services.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Amazon CloudWatch Alarms
Why this is correct
Amazon CloudWatch Alarms are the native mechanism for EC2 AutoRecovery. By configuring an alarm on the System Status Check metric (StatusCheckFailed_System) with the 'recover' action, you let EC2 automatically restart the instance on new hardware while preserving its instance ID, private IP, Elastic IP, and instance store data. This is the direct, built-in solution that requires no custom code or additional orchestration.
- ✗
AWS Lambda
Why it's wrong here
AWS Lambda can technically automate instance recovery by using a custom function that reacts to CloudWatch Events, checks status, and issues stop-instance/start-instance calls. However, this approach adds operational overhead: you must write and maintain code, grant IAM permissions, pay for function invocations, and handle edge cases like instance state transitions. Lambda is a workaround, not the native AutoRecovery feature, which is simpler and more reliable.
- ✗
AWS Systems Manager Automation
Why it's wrong here
AWS Systems Manager Automation executes runbooks that encode manual or scheduled remediation steps, such as restarting a service or replacing an unhealthy instance. While you could build a runbook to recover an instance, it does not automatically respond to Amazon CloudWatch status check failures on its own; you would still need a CloudWatch alarm to trigger the automation via an EventBridge rule. This makes it an indirect and more complex remediation path compared to the built-in CloudWatch 'recover' action.
- ✗
EC2 Auto Scaling
Why it's wrong here
EC2 Auto Scaling is designed for horizontal scaling and fleet management, not for recovering an individual failed instance. When an instance behind an Auto Scaling group fails its health check, the group terminates it and launches a replacement, which changes the instance ID and any attached resources—unlike AutoRecovery, which preserves the original instance. For a standalone EC2 instance that must be recovered in place, Auto Scaling is an inappropriate tool because it replaces rather than recovers.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-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 DOP-C02 exam.