Instantly Create a Multi-AZ Network with CloudFormation

Hello, I'm Tomada.

I wanted to experiment with various things in a multi-AZ configuration for validation purposes, so I'm sharing a CloudFormation template that allows you to create and destroy just the network (VPC) environment.

Architecture Created

Considering that EC2 instances might be placed later, I have also included an Internet Gateway and a NAT Gateway.

• VPC x 1
• Availability Zone 1 (ap-northeast-1a)
  • Public Subnet
  • NAT Gateway
  • Private Subnet
• Availability Zone 2 (ap-northeast-1c)
  • Public Subnet
  • Private Subnet
• Internet Gateway

Full Template

AWSTemplateFormatVersion: 2010-09-09

Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
      -
        Label:
          default: Stack Configuration
        Parameters:
          - EnvironmentName
          - ProjectName
      -
        Label:
          default: VPC Configuration
        Parameters:
          - Region
          - VpcCIDR
          - AZ1PublicSubnetCIDR
          - AZ1PrivateSubnetCIDR
          - AZ2PublicSubnetCIDR
          - AZ2PrivateSubnetCIDR

Parameters:
  EnvironmentName:
    Description: Name which you can specify the environment by this name
    Type: String
    Default: dev
    AllowedValues:
      - dev
      - stg
      - prd
  ProjectName:
    Type: String
    Default: Practice
    Description: Project Name
  VpcCIDR:
    Type: String
    Default: 10.100.0.0/16
  AZ1PublicSubnetCIDR:
    Type: String
    Default: 10.100.1.0/24
  AZ1PrivateSubnetCIDR:
    Type: String
    Default: 10.100.2.0/24
  AZ2PublicSubnetCIDR:
    Type: String
    Default: 10.100.3.0/24
  AZ2PrivateSubnetCIDR:
    Type: String
    Default: 10.100.4.0/24
  Region:
    Type: String
    Default: ap-northeast-1
    Description: Please choose the region.

Resources:
  # --------------------------------------
  # VPC and common resources between AZs
  # --------------------------------------
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref VpcCIDR
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-VPC

  InternetGateway:
    Type: AWS::EC2::InternetGateway
    Properties:
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-InternetGateway
  AttachInternetGateway:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId : !Ref InternetGateway
      VpcId: !Ref VPC

  # --------------------------------------
  # AZ1 (ap-northeast-1a) resources
  # --------------------------------------
  # Public Subnet
  AZ1PublicSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: !Ref AZ1PublicSubnetCIDR
      MapPublicIpOnLaunch: false
      VpcId: !Ref VPC
      AvailabilityZone: !Select
        - 0
        - Fn::GetAZs: !Ref AWS::Region
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ1-PublicSubnet
  # Private Subnet
  AZ1PrivateSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: !Ref AZ1PrivateSubnetCIDR
      MapPublicIpOnLaunch: false
      VpcId: !Ref VPC
      AvailabilityZone: !Select
        - 0
        - Fn::GetAZs: !Ref AWS::Region
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ1-PrivateSubnet
  # Route Table (Public Subnet)
  AZ1RouteTableForPublicSubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ1-RouteTableForPublicSubnet
  # Route for Internet (Internet Gateway) in Public Subnet
  AZ1RouteForPublicSubnet:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref AZ1RouteTableForPublicSubnet
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway
  # Route Association
  AssocciateAZ1RouteTableForPublicSubnet:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref AZ1RouteTableForPublicSubnet
      SubnetId: !Ref AZ1PublicSubnet
  # NAT EIP
  AZ1NatGatewayEIP:
    Type: AWS::EC2::EIP
    Properties:
      Domain: vpc
  # NAT Gateway
  NatGateway:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId:
        Fn::GetAtt:
          - AZ1NatGatewayEIP
          - AllocationId
      SubnetId: !Ref AZ1PublicSubnet
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-NatGateway
    DependsOn: InternetGateway
  # Route Table (Private Subnet)
  AZ1RouteTableForPrivateSubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ1-RouteTableForPrivateSubnet
  # Route for Internet (NAT Gateway) in Private Subnet
  AZ1RouteForPrivateSubnet:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref AZ1RouteTableForPrivateSubnet
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway
  # Route Association
  AssocciateAZ1RouteTableForPrivateSubnet:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref AZ1RouteTableForPrivateSubnet
      SubnetId: !Ref AZ1PrivateSubnet

  # --------------------------------------
  # AZ2 (ap-northeast-1c) resources
  # --------------------------------------
  # Public Subnet
  AZ2PublicSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: !Ref AZ2PublicSubnetCIDR
      MapPublicIpOnLaunch: false
      VpcId: !Ref VPC
      AvailabilityZone: !Select
        - 1
        - Fn::GetAZs: !Ref AWS::Region
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ2-PublicSubnet
  # Private Subnet
  AZ2PrivateSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: !Ref AZ2PrivateSubnetCIDR
      MapPublicIpOnLaunch: false
      VpcId: !Ref VPC
      AvailabilityZone: !Select
        - 1
        - Fn::GetAZs: !Ref AWS::Region
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ2-PrivateSubnet
  # Route Table (Public Subnet)
  AZ2RouteTableForPublicSubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ2-RouteTableForPublicSubnet
  # Route for Internet (Internet Gateway) in Public Subnet
  AZ2RouteForPublicSubnet:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref AZ2RouteTableForPublicSubnet
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway
  # Route Association
  AssocciateAZ2RouteTableForPublicSubnet:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref AZ2RouteTableForPublicSubnet
      SubnetId: !Ref AZ2PublicSubnet
  # Route Table (Private Subnet)
  AZ2RouteTableForPrivateSubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${ProjectName}-${EnvironmentName}-${Region}-AZ2-RouteTableForPrivateSubnet
  # Route for Internet (NAT Gateway) in Private Subnet
  AZ2RouteForPrivateSubnet:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref AZ2RouteTableForPrivateSubnet
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway
  # Route Association
  AssocciateAZ2RouteTableForPrivateSubnet:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref AZ2RouteTableForPrivateSubnet
      SubnetId: !Ref AZ2PrivateSubnet

Parameters

You will be asked to specify the environment name, project name, and CIDR for each subnet.

By the way, the template is designed to automatically select two available AZs within the specified region, in the order they appear.
(In the case of the Tokyo region, this would be in the order of 1a and 1c.)

...
  # --------------------------------------
  # AZ1 ((ap-noatheast-1c) resources
  # --------------------------------------
  # PublicSubnet
  AZ1PublicSubnet:
  ...
      AvailabilityZone: !Select
        - 0
        - Fn::GetAZs: !Ref AWS::Region
...

As long as the region has at least two AZs, this should be applicable to regions other than Tokyo (ap-northeast-1).