vpc_infra.yml

AWSTemplateFormatVersion: "2010-09-09"

Description: > #About the template
  This temple is to deploy the necessary networking infrastructure on with 2 public and 2 private subnets
  VPC CIDR: 10.0.0.0/16
  subnet CIDR: 10.0.0.0/24 (for each public and private subnet)

Parameters: #Values to pass at runtime
  EnvironmentName: 
    Description: Name the environment to prefix as the resource name
    Type: String
  VpcCIDR: 
    Description: IP range for this VPC
    Type: String
    Default: 10.0.0.0/16
  PublicSubnet1CIDR:
    Description: IP range for public subnet 1
    Type: String
    Default: 10.0.0.0/24
  PublicSubnet2CIDR: 
    Description: IP range for public subnet 2
    Type: String
    Default: 10.0.1.0/24
  PrivateSubnet1CIDR:
    Description: IP range for private subnet 1
    Type: String
    Default: 10.0.2.0/24
  PrivateSubnet2CIDR:
    Description: IP range for private subnet 2
    Type: String
    Default: 10.0.3.0/24

Resources:
  WebAppVPC: #Creatting VPC
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref VpcCIDR
      EnableDnsHostnames: true #Indicates whether instances with public IP addresses get corresponding public DNS hostnames
      Tags: 
        - Key: Name
          Value: !Ref EnvironmentName
  InternetGateway: #Creating IG
    Type: AWS::EC2::InternetGateway
    Properties: 
      Tags: 
        - Key: Name
          Value: !Ref EnvironmentName
  InternetGatewayAttachment: #IG Attached to VPC
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId: !Ref InternetGateway
      VpcId: !Ref WebAppVPC
  
  PublicSubnet1:  #Creating Subnets
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref WebAppVPC
      AvailabilityZone: !Select [0, !GetAZs ''] #inline list/array
      CidrBlock: !Ref PublicSubnet1CIDR
      MapPublicIpOnLaunch: true #Indicates whether instances launched in this subnet receive a public IPv4 address.
      Tags: 
        - Key: Name
          Value: !Join [" ", [Pub1, !Ref EnvironmentName]]
  PublicSubnet2:
    Type: AWS::EC2::Subnet
    Properties: 
      VpcId: !Ref WebAppVPC
      AvailabilityZone: !Select [1, !GetAZs '']
      CidrBlock: !Ref PublicSubnet2CIDR
      MapPublicIpOnLaunch: true
      Tags: 
        - Key: Name
          Value: !Sub Pub2 ${EnvironmentName} # same as !Join [" " [Pub2, !Ref EnvironmentName]]
  PrivateSubnet1: #Creating Private Subnet
    Type: AWS::EC2::Subnet
    Properties: 
      VpcId: !Ref WebAppVPC
      AvailabilityZone: !Select [0, !GetAZs '']
      CidrBlock: !Ref PrivateSubnet1CIDR
      MapPublicIpOnLaunch: false
      Tags: 
        - Key: Name
          Value: !Join [" ", [priv1, !Ref EnvironmentName]]
  PrivateSubnet2:
    Type: AWS::EC2::Subnet
    Properties: 
      VpcId: !Ref WebAppVPC
      CidrBlock: !Ref PrivateSubnet2CIDR
      AvailabilityZone: !Select [1, !GetAZs '']
      MapPublicIpOnLaunch: false
      Tags: 
        - Key: Name
          Value: !Join [" ", [priv2, !Ref EnvironmentName]]
  
  NatGatewayEIP1: #Getting EIP before attached to NAT Gateway
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment #required if associated domain is vpc
    Properties:
      Domain: vpc #Alowed values standers | vpc
      Tags: 
        - Key: Name
          Value: !Sub EIP1 for NatGateway1 in ${EnvironmentName}
  NatGatewayEIP2: 
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment
    Properties: 
      Domain: vpc
      Tags: 
        - Key: Name
          Value: !Sub EIP2 for NatGateway2 in ${EnvironmentName}
  NatGateway1:  #Creating NAT Gateway
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGatewayEIP1.AllocationId
      SubnetId: !Ref PublicSubnet1
  NatGateway2:
    Type: AWS::EC2::NatGateway
    Properties: 
      AllocationId: !GetAtt NatGatewayEIP2.AllocationId
      SubnetId: !Ref PublicSubnet2
  
  PublicRouteTable: #Creating Public Route Table
    Type: AWS::EC2::RouteTable
    Properties: 
      VpcId: !Ref WebAppVPC
      Tags: 
        - Key: Name
          Value: !Sub Public Route for ${EnvironmentName}
  DefaultPublicRoute:  #Creating Public Route to send traffic to Internet Gateway
    Type: AWS::EC2::Route
    Properties: 
      RouteTableId: !Ref PublicRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway
  PublicSubnet1RouteTableAssociation: 
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties: 
      RouteTableId: !Ref PublicRouteTable
      SubnetId: !Ref PublicSubnet1
  PublicSubnet2RouteTableAssociation: 
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties: 
      SubnetId: !Ref PublicSubnet2
      RouteTableId: !Ref PublicRouteTable
  
  PrivateRouteTable1: #Creating Private Route  table for NAT Gateway1
    Type: AWS::EC2::RouteTable
    Properties: 
      VpcId: !Ref WebAppVPC
      Tags: 
        - Key: Name
          Value: !Sub Priv-Rout-Tab1 for ${EnvironmentName}
  PrivateRouteTable2: 
    Type: AWS::EC2::RouteTable
    Properties: 
      VpcId: !Ref WebAppVPC
      Tags: 
        - Key: !Ref WebAppVPC
          Value: !Sub priv-Rout-Tab2 for ${EnvironmentName}
  DefaultPrivateRoute1: #Creating default Routes to  private RTs
    Type: AWS::EC2::Route
    Properties: 
      RouteTableId: !Ref PrivateRouteTable1
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway1
  DefaultPrivateRoute2:
    Type: AWS::EC2::Route
    Properties: 
      RouteTableId: !Ref PrivateRouteTable2
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway2
  PrivateSubnet1RouteTableAssociation: #Private route table association
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties: 
      RouteTableId: !Ref PrivateRouteTable1
      SubnetId: !Ref PrivateSubnet1
  PrivateSubnet2ROuteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties: 
      RouteTableId: !Ref PrivateRouteTable2
      SubnetId: !Ref PrivateSubnet2

Outputs: 
  WebAppVPCOutput: 
    Description: A reference to the WebAPPVPC
    Value: !Ref WebAppVPC
    Export: 
      Name: !Sub ${EnvironmentName}-WebAppVPCId
  VpcPublicRouteTable: 
    Description: Public Route Table for public subnets in WebAppVPC
    Value: !Ref PublicRouteTable
    Export: 
      Name: !Sub ${EnvironmentName}-PUB-RT
  VpcPrivateRouteTable1: 
    Description: Private Route Table 1 for private subnet 1 in WebAppVPC
    Value: !Ref PrivateRouteTable1
    Export: 
      Name: !Sub ${EnvironmentName}-PRIV-RT-1
  VpcPrivateRouteTable2: 
    Description: Private Route Table 2 for private Subnet 2 in WebAppVPC
    Value: !Ref PrivateRouteTable2
    Export: 
      Name: !Sub ${EnvironmentName}-PRIV-RT-2
  
  PublicSubnets: #These are for AutoScalingGroup
    Description: A list of Public Subnets
    Value: !Join [",", [!Ref PublicSubnet1, !Ref PublicSubnet2]]
    Export: 
      Name: !Sub ${EnvironmentName}-Public-Subnets
  PrivateSubnets: #These are for AutoScalingGroup VPCZoneIdentifier
    Description: A list of Private Subnets
    Value: !Join [",", [!Ref PrivateSubnet1, !Ref PrivateSubnet2]]
    Export: 
      Name: !Sub ${EnvironmentName}-Private-Subnets
  
  PublicSubnet1Out: 
    Description: A reference to the Public Subnet 1 in WebAppVPC
    Value: !Ref PublicSubnet1
    Export: 
      Name: !Sub ${EnvironmentName}-PUB-SUB-1
  PublicSubnet2Out: 
    Description: A reference to the Public Subnet 2 in WebAppVpc
    Value: !Ref PublicSubnet2
    Export: 
      Name: !Sub ${EnvironmentName}-PUB-SUB-2
  PrivateSubnet1Out:
    Description: A reference to the Private Subnet 1 in WebAppVPC
    Value: !Ref PrivateSubnet1
    Export: 
      Name: !Sub ${EnvironmentName}-PRIV-SUB-1
  PrivateSubnet2Out: 
    Description: A reference to the Private Subnet 2 in WebAppVPC
    Value: !Ref PrivateSubnet2
    Export: 
      Name: !Sub ${EnvironmentName}-PRIV-SUB-2