In this recipe, you will create a new CloudFormation that creates a stack with a NAT gateway. Let's get started:

1. Start with the usual CloudFormation template version and description:

AWSTemplateFormatVersion: "2010-09-09" 
Description: Create NAT Gateway and associated route.

2. The template must take the following required parameters:

Parameters: 
  PublicSubnetId: 
    Description: Public Subnet ID to add the NAT Gateway to 
    Type: AWS::EC2::Subnet::Id 
  RouteTableId: 
    Description: The private subnet route table to add the NAT
    Gateway route to 
    Type: String

3. In the Resources section, define an Elastic IP (EIP) that will be assigned to the NAT gateway:

Resources: 
  EIP: 
    Type: AWS::EC2::EIP 
    Properties: 
      Domain: vpc

4. Create the NAT gateway resource, assigning it the EIP you just defined in the public subnet:

  NatGateway: 
    Type: AWS::EC2::NatGateway 
    Properties: 
      AllocationId: !GetAtt EIP.AllocationId 
      SubnetId: !Ref PublicSubnetId

5. Finally, define the route to the NAT gateway and associate it with the private subnet's route table:

  Route: 
    Type: AWS::EC2::Route 
    Properties: 
      RouteTableId: !Ref RouteTableId 
      DestinationCidrBlock: 0.0.0.0/0 
      NatGatewayId: !Ref NatGateway

6. Save the template with a known filename, for example, 07-02-NATGateway.yaml.
7. Launch the template with the following CLI command:

      aws cloudformation create-stack 
        --stack-name nat-gateway 
        --template-body file://07-02-NATGateway.yaml 
        --parameters 
        ParameterKey=RouteTableId,ParameterValue=<route-table-id> 
        ParameterKey=PublicSubnetId,ParameterValue=<public-subnet-id>