EC2 hardware status

Sometimes you may find out that your EC2 instances were unexpected rebooted. You may wonder whether the root cause is purely software or related with underlying physical hardware. Status check of CloudWatch could provide useful insight via StatusCheckFailed_System, which is an indicator of its physical health status.

REF: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html