How to Create a Site-to-Site VPN in CloudFormation

To create a site-to-site VPN (Virtual Private Network) using AWS CloudFormation, you can use the AWS::EC2::VPNGateway and AWS::EC2::VPNConnection resources. Here’s an example CloudFormation template to create a site-to-site VPN:

AWSTemplateFormatVersion: '2010-09-09'
Resources:
  VpnGateway:
    Type: AWS::EC2::VPNGateway
    Properties:
      Type: ipsec.1
      Tags:
        - Key: Name
          Value: SiteToSiteVPN

  VpnConnection:
    Type: AWS::EC2::VPNConnection
    Properties:
      Type: ipsec.1
      CustomerGatewayId: <CUSTOMER_GATEWAY_ID>
      VpnGatewayId: !Ref VpnGateway
      StaticRoutesOnly: true
      Tags:
        - Key: Name
          Value: SiteToSiteVPNConnection

  VpnConnectionRoute:
    Type: AWS::EC2::VPNConnectionRoute
    Properties:
      DestinationCidrBlock: <DESTINATION_CIDR_BLOCK>
      VpnConnectionId: !Ref VpnConnection

In the above template, you need to replace <CUSTOMER_GATEWAY_ID> with the ID of the customer gateway representing the remote site, and <DESTINATION_CIDR_BLOCK> with the CIDR block of the remote network you want to connect to.

This template creates a VPN gateway (VpnGateway) and a VPN connection (VpnConnection). It also creates a VPN connection route (VpnConnectionRoute) to specify the destination CIDR block that should be routed through the VPN connection.

Note that you may need to modify the template based on your specific requirements, such as configuring the customer gateway or making additional network adjustments.

Once you have the CloudFormation template ready, you can create the stack using the AWS CloudFormation console, AWS CLI, or AWS SDKs. The stack creation process will provision the necessary resources to establish the site-to-site VPN connection.