hostname
Parameters
value
The type of hostnames to assign to instances in the subnet at launch. For IPv4 only subnets, an instance DNS name must be based on the instance IPv4 address. For IPv6 only subnets, an instance DNS name must be based on the instance ID. For dual-stack subnets, you can specify whether DNS names use the instance IPv4 address or the instance ID. For more information, see Amazon EC2 instance hostname types in the Amazon Elastic Compute Cloud User Guide.