elb-to-ec2-target-group-cf-template.yml

# Copyright [2024] [Phil Chen]

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#    http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

AWSTemplateFormatVersion: 2010-09-09
Description: Creates a VPC and a ELB with a EC2 Target Group Associated

Parameters:

    SSHKeyName:
        Description: 'Name of the ec2 key you need one to use this template'
        Type: 'AWS::EC2::KeyPair::KeyName'
        Default: 'choose-key'

Mappings:

    RegionToAmazonAMI:
        us-east-1:
            HVM64: ami-09479453c5cde9639
        us-east-2:
            HVM64: ami-023c8dbf8268fb3ca
        us-west-1:
            HVM64: ami-06ff511fea5db2c99
        us-west-2:
            HVM64: ami-0bb5806b2e825a199

    NetworkToSubnet:
        "10.0.0.0":
            PubSubnetZoneA: "10.0.10.0/24"
            PrivSubnetZoneA: "10.0.20.0/24"
            PubSubnetZoneB: "10.0.30.0/24"
            PrivSubnetZoneB: "10.0.40.0/24"

Resources:

    # VPC
    VPC:
        Type: 'AWS::EC2::VPC'
        Properties:
            CidrBlock:
                'Fn::Join': [ '/', [ '10.0.0.0', '16' ] ]
            EnableDnsSupport: true
            EnableDnsHostnames: true
            InstanceTenancy: 'default'
            Tags:
                - Key: 'Name'
                  Value:
                      Ref: 'AWS::StackName'

    # Internet accessable subnet in the first availability zone
    PubSubnetZoneA:
        Type: 'AWS::EC2::Subnet'
        Properties:
            AvailabilityZone:
                Fn::Select:
                - '0'
                - Fn::GetAZs:
                    Ref: 'AWS::Region'
            CidrBlock:
                Fn::FindInMap:
                - NetworkToSubnet
                - '10.0.0.0'
                - PubSubnetZoneA
            MapPublicIpOnLaunch: 'True'
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Public', 'Zone A', !Ref 'AWS::StackName' ] ]

    # Non-internet accessable subnet in the first availability zone
    PrivSubnetZoneA:
        Type: 'AWS::EC2::Subnet'
        Properties:
            AvailabilityZone:
                Fn::Select:
                - '0'
                - Fn::GetAZs:
                    Ref: 'AWS::Region'
            CidrBlock:
                Fn::FindInMap:
                - NetworkToSubnet
                - '10.0.0.0'
                - PrivSubnetZoneA
            MapPublicIpOnLaunch: 'False'
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Private', 'Zone A', !Ref 'AWS::StackName' ] ]

    # Internet accessable subnet in the second availability zone
    PubSubnetZoneB:
        Type: 'AWS::EC2::Subnet'
        Properties:
            AvailabilityZone:
                Fn::Select:
                - '1'
                - Fn::GetAZs:
                    Ref: 'AWS::Region'
            CidrBlock:
                Fn::FindInMap:
                - NetworkToSubnet
                - '10.0.0.0'
                - PubSubnetZoneB
            MapPublicIpOnLaunch: 'True'
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Public', 'Zone B', !Ref 'AWS::StackName' ] ]

    # Non-internet accessable subnet in the second availability zone
    PrivSubnetZoneB:
        Type: 'AWS::EC2::Subnet'
        Properties:
            AvailabilityZone:
                Fn::Select:
                - '1'
                - Fn::GetAZs:
                    Ref: 'AWS::Region'
            CidrBlock:
                Fn::FindInMap:
                - NetworkToSubnet
                - '10.0.0.0'
                - PrivSubnetZoneB
            MapPublicIpOnLaunch: 'False'
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Private', 'Zone B', !Ref 'AWS::StackName' ] ]

    # Gateway to the internet
    InternetGateway:
        Type: 'AWS::EC2::InternetGateway'
        Properties:
            Tags:
                - Key: 'Name'
                  Value:
                      Ref: 'AWS::StackName'

    # Associate the gateway to the VPC
    GatewayAttachment:
        Type: AWS::EC2::VPCGatewayAttachment
        Properties:
            InternetGatewayId:
                Ref: 'InternetGateway'
            VpcId:
                Ref: 'VPC'

    # Routing table for the public subnet in availability zone A
    RouteTablePubZoneA:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Public', 'Zone A', !Ref 'AWS::StackName' ] ]

    # Routing table for the public subnet in availability zone B
    RouteTablePubZoneB:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Public', 'Zone B', !Ref 'AWS::StackName' ] ]

    # Route traffic through the internet gateway
    RoutePubZoneA:
        Type: AWS::EC2::Route
        Properties:
            DestinationCidrBlock: '0.0.0.0/0'
            GatewayId:
                Ref: 'InternetGateway'
            RouteTableId:
                Ref: 'RouteTablePubZoneA'

    # Route traffic through the internet gateway
    RoutePubZoneB:
        Type: AWS::EC2::Route
        Properties:
            DestinationCidrBlock: 0.0.0.0/0
            GatewayId:
                Ref: 'InternetGateway'
            RouteTableId:
                Ref: 'RouteTablePubZoneB'

    # Associate public subnet to its routing table
    RouteAssociationPubSubnetZoneA:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            SubnetId:
                Ref: 'PubSubnetZoneA'
            RouteTableId:
                Ref: 'RouteTablePubZoneA'

    # Associate public subnet to its routing table
    RouteAssociationPubSubnetZoneB:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            SubnetId:
                Ref: 'PubSubnetZoneB'
            RouteTableId:
                Ref: 'RouteTablePubZoneB'

    # Routing table for the private subnet in availability zone A
    RouteTablePrivZoneA:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Private', 'Zone A', !Ref 'AWS::StackName' ] ]

    # Routing table for the private subnet in availability zone B
    RouteTablePrivZoneB:
        Type: AWS::EC2::RouteTable
        Properties:
            VpcId:
                Ref: 'VPC'
            Tags:
                - Key: 'Name'
                  Value:
                      'Fn::Join': [ ':', [ 'Private', 'Zone B', !Ref 'AWS::StackName' ] ]

    # Associate the private subnet with its routing table
    RouteAssociationPrivSubnetZoneA:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            SubnetId:
                Ref: 'PrivSubnetZoneA'
            RouteTableId:
                Ref: 'RouteTablePrivZoneA'

    # Associate the private subnet with its routing table
    RouteAssociationPrivSubnetZoneB:
        Type: AWS::EC2::SubnetRouteTableAssociation
        Properties:
            SubnetId:
                Ref: 'PrivSubnetZoneB'
            RouteTableId:
                Ref: 'RouteTablePrivZoneB'

    # EC2 Security Group Allowing Port 22 and 80 from anywhere
    EC2SecurityGroup:
        Type: AWS::EC2::SecurityGroup
        Properties:
            GroupDescription: 'SSH and Port 80'
            VpcId:
              Ref: VPC
            SecurityGroupIngress:
                - IpProtocol: tcp
                  FromPort: 22
                  ToPort: 22
                  CidrIp: 0.0.0.0/0
                - IpProtocol: tcp
                  FromPort: 80
                  ToPort: 80
                  SourceSecurityGroupId:
                      Ref: ELBSecurityGroup

    # ELB Security Group allowing Port 80 from anywhere
    ELBSecurityGroup:
        Type: AWS::EC2::SecurityGroup
        Properties:
            GroupDescription: 'SSH and Port 80'
            VpcId:
              Ref: VPC
            SecurityGroupIngress:
                - IpProtocol: tcp
                  FromPort: 80
                  ToPort: 80
                  CidrIp: 0.0.0.0/0

    # Linux Instance with Apache running on Port 80
    AmazonLinuxInstance:
      Type: AWS::EC2::Instance
      Properties:
        ImageId:
          Fn::FindInMap:
            - RegionToAmazonAMI
            - Ref: 'AWS::Region'
            - HVM64
        InstanceInitiatedShutdownBehavior: stop
        InstanceType: t2.nano
        KeyName:
          Ref: SSHKeyName
        Monitoring: 'true'
        NetworkInterfaces:
        - AssociatePublicIpAddress: 'true'
          DeviceIndex: '0'
          GroupSet:
          - !Ref EC2SecurityGroup
          SubnetId:
            Ref: PubSubnetZoneA
        Tenancy: default
        UserData:
          Fn::Base64: !Sub |
            #!/bin/bash -xe
            cd /tmp
            yum update -y
            yum install -y httpd24
            echo "Healthy" > /var/www/html/index.html
            service httpd start
            /opt/aws/bin/cfn-signal \
              -e $? \
              --stack ${AWS::StackName} \
              --resource AmazonLinuxInstance \
              --region ${AWS::Region}

    # Target Group
    EC2TargetGroup:
      Type: AWS::ElasticLoadBalancingV2::TargetGroup
      Properties:
        HealthCheckIntervalSeconds: 30
        HealthCheckProtocol: HTTP
        HealthCheckTimeoutSeconds: 15
        HealthyThresholdCount: 5
        Matcher:
          HttpCode: '200'
        Name: EC2TargetGroup
        Port: 80
        Protocol: HTTP
        TargetGroupAttributes:
        - Key: deregistration_delay.timeout_seconds
          Value: '20'
        Targets:
        - Id:
            Ref: AmazonLinuxInstance
          Port: 80
        UnhealthyThresholdCount: 3
        VpcId:
          Ref: 'VPC'
        Tags:
        - Key: Name
          Value: EC2TargetGroup
        - Key: Port
          Value: 80

    #ELB (ALB)
    ALBListener:
      Type: AWS::ElasticLoadBalancingV2::Listener
      Properties:
        DefaultActions:
          - Type: forward
            TargetGroupArn:
              Ref: EC2TargetGroup
        LoadBalancerArn:
            Ref: ApplicationLoadBalancer
        Port: 80
        Protocol: HTTP
    ApplicationLoadBalancer:
      Type: AWS::ElasticLoadBalancingV2::LoadBalancer
      Properties:
        Scheme: internet-facing # or internal
        Subnets:
        - Ref: PubSubnetZoneA
        - Ref: PubSubnetZoneB
        SecurityGroups:
        - Ref: ELBSecurityGroup

Outputs:

    VPC:
        Description: 'Virtual Private Cloud'
        Value:
          Ref: 'VPC'
    ALBHostName:
        Description: 'Application Load Balancer Hostname'
        Value:
          !GetAtt ApplicationLoadBalancer.DNSName
    EC2Instance:
        Description: 'EC2 Instance'
        Value:
          Ref: AmazonLinuxInstance
    EC2TargetGroup:
        Description: 'EC2 Target Group'
        Value:
          Ref: EC2TargetGroup
    ApplicationLoadBalancer:
        Description: 'Application Load Balancer'
        Value:
          Ref: ApplicationLoadBalancer