Using CloudFormation and Terraform

When it comes to automating the setup of VPC-to-VPC interactions in AWS, two popular tools are CloudFormation and Terraform.

CloudFormation

CloudFormation is an AWS service that enables you to define your infrastructure as code. You can use JSON or YAML templates to describe the resources and dependencies needed to set up your VPC-to-VPC interactions.

With CloudFormation, you can define the networking components, such as VPCs, subnets, security groups, and route tables, as well as the necessary configurations for peering connections, VPN connections, and transit gateways.

Here's an example CloudFormation template that creates a VPC with two subnets and a peering connection:

1Resources:
2  MyVPC:
3    Type: AWS::EC2::VPC
4    Properties:
5      CidrBlock: 10.0.0.0/16
6      EnableDnsHostnames: true
7  SubnetA:
8    Type: AWS::EC2::Subnet
9    Properties:
10      VpcId: !Ref MyVPC
11      CidrBlock: 10.0.0.0/24
12  SubnetB:
13    Type: AWS::EC2::Subnet
14    Properties:
15      VpcId: !Ref MyVPC
16      CidrBlock: 10.0.1.0/24
17  PeeringConnection:
18    Type: AWS::EC2::VPCPeeringConnection
19    Properties:
20      VpcId: !Ref MyVPC
21      PeerVpcId: <peer vpc id>

Terraform

Terraform is an open-source infrastructure as code tool created by HashiCorp. It allows you to write declarative configuration files using HashiCorp Configuration Language (HCL) to define and manage your infrastructure.

With Terraform, you can define your VPC-to-VPC interactions using the same resources and configurations as CloudFormation, but with a different syntax.

Here's an example Terraform configuration that creates the same VPC with two subnets and a peering connection as the CloudFormation template mentioned above:

1resource "aws_vpc" "my_vpc" {
2  cidr_block = "10.0.0.0/16"
3  enable_dns_hostnames = true
4}
5
6resource "aws_subnet" "subnet_a" {
7  vpc_id = aws_vpc.my_vpc.id
8  cidr_block = "10.0.0.0/24"
9}
10
11resource "aws_subnet" "subnet_b" {
12  vpc_id = aws_vpc.my_vpc.id
13  cidr_block = "10.0.1.0/24"
14}
15
16resource "aws_vpc_peering_connection" "peering_connection" {
17  vpc_id = aws_vpc.my_vpc.id
18  peer_vpc_id = <peer vpc id>
19}

Using CloudFormation and Terraform provides a way to automate the setup and configuration of your VPC-to-VPC interactions. By defining your infrastructure as code, you can version, test, and deploy your configurations more efficiently.

Remember to replace <peer vpc id> in both the CloudFormation and Terraform examples with the actual ID of the VPC you want to peer with.

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import com.amazonaws.services.cloudformation.*;

import com.hashicorp.*;

​

class Main {

  public static void main(String[] args) {

    // replace with your Java logic here

    AWSCloudFormationClient cloudFormationClient = new AWSCloudFormationClient();

    HashicorpTerraformClient terraformClient = new HashicorpTerraformClient();

    cloudFormationClient.createStack("my-vpc-stack");

    terraformClient.apply("my-vpc-infrastructure");

  }

}