Why did my EC2 instance become unreachable before the scheduled retirement date?

Resolution

Amazon EC2 creates a scheduled event when the infrastructure systems that host the instance's underlying hardware detect an irreparable failure. During this time, the underlying hardware might become inaccessible and unable to host instances. As a result, the instance becomes unreachable before the scheduled retirement date. If the instance becomes unreachable before the scheduled retirement date, then stop and start it to move it to new, healthy hardware.

The retirement notification includes the status of the underlying hardware and whether the instance is reachable. You typically receive retirement notices in advance so that you can stop and start the instance at a time that's convenient to your usage patterns. The retirement notice includes instance retirement information and recommended actions for the scheduled retirement event.