When a CloudWatch alarm detects a hung service on an instance, the system should automatically restart it without human involvement. Which pattern implements self-healing?
A.Alarm → SNS → pager for manual restart
Manual response — the requirement is automatic.
B.Alarm → EventBridge → SSM Automation runbook performing the restart
Correct. Alarm-driven runbook execution.
C.Scheduled Lambda checking every 5 minutes
Polling + DIY logic vs native event triggers.
D.ASG replacing instances on a schedule
Replaces whole instances for a service-level issue.
Why this answer
EventBridge-triggered SSM Automation is the canonical remediation loop: alarm → event → runbook executes defined fix steps. This is the pattern AWS documents for auto-remediation; polling adds latency, and instance replacement is heavier than a service restart.
Correct answer: B · Last reviewed 2026-11-04
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