Enabling VPC for a Farm
To use VPC with a Farm, ensure that you check "Launch this Farm inside Amazon VPC". Then, select the VPC the Farm should be launched in.
Note that a VPC Policy can be defined to ensure all Farms are launched in a VPC, as well as to control the VPCs and Subnets that may be used.
Configuring Farm Roles in a VPC-enabled Farm
Note that you must select at least one Subnet. If you opt to use more than one, the Servers (Instances) for this Farm Role will be evenly distributed across the subnets.
Please be aware that VPC farm settings affecting ONLY AWS Farm Roles / Roles. You will be able to add Farm Roles from other cloud providers to a VPC enabled farm regardless of VPC settings.
There are specific considerations pertaining to each type of Subnet. Review them here: