Virtual Private Cloud (VPC)¶
Amazon Virtual Private Cloud (Amazon VPC) lets you provision a logically isolated section of the Amazon Web Services (AWS) Cloud where you can launch AWS resources in a virtual network that you define. Click here to learn more about VPC.
Rackspace Base Network VPC¶
For most Fanatical Support for AWS customers, Rackspace recommends the deployment of a single VPC per AWS account to provide operational simplicity while meeting stringent security requirements. Segregation will be accomplished by creating Public and Private subnets, and by relying on carefully created Security Groups that only allow the required granular access (further details in the Security section).
If further segregation were required to control access (e.g. Production vs. Test vs. Development), Rackspace's recommendation is to create a separate AWS accounts, and not a separate VPC in the same AWS account. This is because a second VPC in the same AWS account does not provide control plane isolation of resources, and could complicate ongoing operational processes.
You can assign a single CIDR block to a VPC. The allowed block size is between a /28 netmask and /16 netmask. In other words, the VPC can contain from 16 to 65,536 IP addresses. You cannot change the size of a VPC after you have created it. If your VPC is too small to meet your needs, you will need to create a new, larger VPC, and then migrate your instances to the new VPC.
The VPC requires an RFC 1918 CIDR range (Private addresses). The default is a /16 network, however, you need to carefully consider the range you select to ensure the range does not overlap with your other environments (on premise, other AWS VPCs, Rackspace dedicated environments, etc.).
The CloudFormation template captures the CIDR range in the Parameter: VPCCIDR. Detailed IP addressing recommendations will be discussed in the Subnets section. The BaseNetwork CloudFormation template's default VPC CIDR is 172.18.0.0/16.