I've gotten emails a week in advance and again a day in advance when an instance needed maintenance that would result in a 10 second network reset, so it'd really surprise me if Amazon completely retired an instance with no notification. This person must have missed the email or it got spammed.
One or more of your Amazon EC2 instances have been scheduled for
maintenance. The maintenance will result in a reset of the network
connection for your instance(s). The network reset will cause all
current connections to your instance(s) to be dropped. The network
reset will take less than 1 second to complete. Once complete your
instance(s) network connectivity will be restored. The instance(s)
will have their network connections reset during the time window
listed below.
You can avoid having your network connection reset at the specified
time by rebooting your instance(s) prior to the maintenance window. To
manage an instance reboot yourself you can issue an EC2 instance
reboot command. This can be done easily from the AWS Management
Console at http://console.aws.amazon.com by first selecting your
instance and then choosing ‘Reboot’ from the ‘Instance Actions’ drop
down box.
It looks like the forum thread has been updated with the following comment from Luke@AWS
> I just looked into your instance a bit further, it does appear this was due to an issue with the underlying host on which your instance resided upon when you encountered the issues today.
> I do want to clarify here as our original reply mentioned a scheduled retirement, this was not the case and no notice was sent out because of this.
It looks like the original email was incorrect.
To add to this though if people rely on advance email notifications with AWS then they are putting at risk their availability. Just because it is on the cloud doesn't insulate you from hardware issues, these need to be planned for. AWS does provide some building blocks to address this (auto-scalaing and load balancers come to mind).
It was EBS backed instance, since I had snapshot, it does not took much time to recreate a new instance. Beside that I had another instance behind ELB to avoid downtime.
If is fair to expect some notification for scheduled retirement.