associatePublicIpAddress
Specifies whether to assign a public IPv4 address to the group's instances. If the instance is launched into a default subnet, the default is to assign a public IPv4 address, unless you disabled the option to assign a public IPv4 address on the subnet. If the instance is launched into a nondefault subnet, the default is not to assign a public IPv4 address, unless you enabled the option to assign a public IPv4 address on the subnet. For more information, see Launching Auto Scaling instances in a VPC in the Amazon EC2 Auto Scaling User Guide.