basic_network.yml

AWSTemplateFormatVersion: 2010-09-09
# https://www.infoq.com/articles/aws-vpc-cloudformation/
# This CloudFormation template deploys a basic VPC / Network.
Resources:
  # First, a VPC:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 10.1.0.0/16
      EnableDnsSupport: true
      EnableDnsHostnames: true
      Tags:
      - Key: Name
        Value:  !Join ['', [!Ref "AWS::StackName", "-VPC" ]]
  # Our VPC will need internet access:     
  InternetGateway:
    Type: AWS::EC2::InternetGateway
    DependsOn: VPC
  AttachGateway:
    Type: AWS::EC2::VPCGatewayAttachment
    # Notice how you can't attach an IGW to a VPC unless both are created:
    Properties:
      VpcId: !Ref VPC
      InternetGatewayId: !Ref InternetGateway
  PublicSubnetA:
      Type: AWS::EC2::Subnet
      Properties:
        VpcId: !Ref VPC
        CidrBlock: 10.1.10.0/24
        # Get the second AZ in the list, because the first AZ would give this error when creating EMR for us-east-1:
        # The requested instance type m3.xlarge is not supported in the requested availability zone
        AvailabilityZone: !Select [ 1, !GetAZs ]    
        MapPublicIpOnLaunch: true
        Tags:
        - Key: Name
          Value: !Sub ${AWS::StackName}-Public-A
  PublicSubnetB:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.1.20.0/24
      AvailabilityZone: !Select [ 2, !GetAZs ]    # Get the third AZ in the list 
      MapPublicIpOnLaunch: true
      Tags:
      - Key: Name
        Value: !Sub ${AWS::StackName}-Public-B
  PrivateSubnetA:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.1.50.0/24
      AvailabilityZone: !Select [ 1, !GetAZs ]    # Get the second AZ in the list 
      Tags:
      - Key: Name
        Value: !Sub ${AWS::StackName}-Private-A
  PrivateSubnetB:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      CidrBlock: 10.1.60.0/24
      AvailabilityZone: !Select [ 2, !GetAZs ]    # Get the third AZ in the list 
      Tags:
      - Key: Name
        Value: !Sub ${AWS::StackName}-Private-B
  # Some route tables for our subnets:
  PublicRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
      - Key: Name
        Value: Public
  PublicRoute1:   # Public route table has direct routing to IGW:
    Type: AWS::EC2::Route
    DependsOn: AttachGateway
    Properties:
      RouteTableId: !Ref PublicRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway
  # Here is a private route table:
  PrivateRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
      - Key: Name
        Value: Private
  PrivateRoute1:            # Private route table can access web via NAT (created below)
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref PrivateRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      # Route traffic through the NAT Gateway:
      NatGatewayId: !Ref NATGateway
  # A NAT Gateway:
  NATGateway:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt ElasticIPAddress.AllocationId
      SubnetId: !Ref PublicSubnetA
      Tags:
      - Key: Name
        Value: !Sub NAT-${AWS::StackName}
  ElasticIPAddress:
    Type: AWS::EC2::EIP
    Properties:
      Domain: vpc
# Attach the public subnets to public route tables,
  # and attach the private subnets to private route tables:   
  PublicSubnetARouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PublicSubnetA
      RouteTableId: !Ref PublicRouteTable
  PublicSubnetBRouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PublicSubnetB
      RouteTableId: !Ref PublicRouteTable
  PrivateSubnetARouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PrivateSubnetA
      RouteTableId: !Ref PrivateRouteTable
  PrivateSubnetBRouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PrivateSubnetB
      RouteTableId: !Ref PrivateRouteTable