Network_automation.yml

AWSTemplateFormatVersion: '2010-09-09'
Description : >-
  This template deploys a VPC and creates following resources in the VPC;
  1 Public and 1 Private Subnet in a single availabilty zone
  1 Internet gateway
  1 NATGateway
  1 Public RouteTable and 1 Private RouteTable
Parameters:
  EnvironmentName:
    Type: String
    Description: Enter a unique id for this stack. This id will be used as a Tag for this deployment
    AllowedPattern: '[a-zA-Z0-9_\-]+'
    ConstraintDescription: It should be a combination of characters from [A-Z],[a-z],[0-9],- and _.
  VpcName:
    Description: Specify the VPC Name
    Type: String
  AvailabilityZone:
    Description: Please select the AvailabilityZone for this deployment
    Type: AWS::EC2::AvailabilityZone::Name
  VpcCIDR:
    Description: Please enter the IP range (CIDR) for this VPC. Must be a /20 range for this example(auto cIDR calcuation). For example, 192.168.0.0/20
    Type: String
    AllowedPattern: ^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])(\/([2][0]))$   # only /20 allowed
Resources:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref VpcCIDR
      EnableDnsSupport: true
      EnableDnsHostnames: true
      Tags:
        - Key: Name
          Value: !Ref VpcName
  InternetGateway:
    Type: AWS::EC2::InternetGateway
    Properties:
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-InternetGateway
  InternetGatewayAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId: !Ref InternetGateway
      VpcId: !Ref VPC
  PublicSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Ref AvailabilityZone
      CidrBlock: !Select [ 0 , !Cidr [ !GetAtt VPC.CidrBlock, 32, 7 ]] # 32 subnets of VpcCIDR range; 128 host addresses; 32-7= /25 Cidr range
      # Use a subnet calculator to  calculate values for !Cidr. For example # https://www.site24x7.com/tools/ipv4-subnetcalculator.html
      MapPublicIpOnLaunch: true # Assign a public IP to the instances launched in this subnet
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-PublicSubnet-${AvailabilityZone}
  PrivateSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Ref AvailabilityZone
      CidrBlock: !Select [ 1 , !Cidr [ !GetAtt VPC.CidrBlock, 8, 9 ]] # 8 subnets of VpcCIDR range; 512 host addresses; 32-9= /23 Cidr range
      MapPublicIpOnLaunch: false
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-PrivateSubnet-${AvailabilityZone}
  NatGatewayEIP:
    Type: AWS::EC2::EIP
    Properties:
      Domain: vpc
  NatGateway:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGatewayEIP.AllocationId
      SubnetId: !Ref PublicSubnet
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-NATGateway-${AvailabilityZone}
  RouteTablePublic:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-PublicRouteTable-${AvailabilityZone}
  PublicRoute:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref RouteTablePublic
      DestinationCidrBlock: 0.0.0.0/0   # Outgoing traffic any:any
      GatewayId: !Ref InternetGateway
  RouteTablePublicAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref RouteTablePublic
      SubnetId: !Ref PublicSubnet
  RouteTablePrivate:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub ${VpcName}-PrivateRouteTable-${AvailabilityZone}
  PrivateRoute:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref RouteTablePrivate
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway
  RouteTablePrivateAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref RouteTablePrivate
      SubnetId: !Ref PrivateSubnet
  NoIngressSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: "no-ingress-sg"
      GroupDescription: "Security group with no ingress rule"
      VpcId: !Ref VPC
Outputs:
  VpcEnvironmentName:
    Description: Name of the Stack which created VPC
    Value: !Sub ${AWS::StackName}
    Export:
      Name: !Sub ${EnvironmentName}-VpcEnvironmentName
  VPC:
    Description: A reference to the created VPC
    Value: !Ref VPC
    Export:
      Name: !Sub ${EnvironmentName}-VPC