Amazon EC2 Dedicated Hosts now supports live migration for host maintenance to improve application uptime and reduce your operational effort. In the event a host requires maintenance, AWS will allocate a replacement Dedicated Host and move your instances to the new host. You are not required to take any action prior to, during, or after live migration.
Amazon EC2 Dedicated Hosts are physical servers fully dedicated for your use. Bring-your-own-license (BYOL) customers can use Dedicated Hosts to reduce costs for commercial software workloads like Microsoft SQL Server. AWS regularly monitors the health of your hosts. In the rare event of a degradation or for planned host maintenance, AWS will move your instances to the replacement host without requiring your instances to be stopped or rebooted.
This feature is available in all commercial AWS Regions.
To learn more, see Host maintenance in the Amazon EC2 User Guide.
Source:: Amazon AWS