2-tier-app-stack.yaml

AWSTemplateFormatVersion: "2010-09-09"
Parameters:
  VpcID:
    Description: VPC used to create the interfaces
    Type: AWS::EC2::VPC::Id
  AmiId:
    Description: EC2 AMI ID
    Type: AWS::EC2::Image::Id
    Default: ami-09d95fab7fff3776c
  Ec2InstanceType:
    Description: EC2 Instance of Web Tier ASG
    Type: String
    Default: t2.micro
  PublicSubnet1:
    Description: subnet ID with a route to IGW
    Type: String
  PublicSubnet2:
    Description: subnet ID with a route to IGW in a different AZ than PublicSubnet1
    Type: String
  PrivateSubnet1:
    Description: Subnet ID with default route to NAT Gateway, this code uses public yum repo
    Type: String
  PrivateSubnet2:
    Description: Subnet ID with Default route to NAT Gateway in different AZ than PrivateSubnet1
    Type: String
  SshKey:
    Description: Name of SSH Key of EC2 Instances
    Type: String
  DBInstanceType:
    Description: Hardware Class DB is run on 
    Type: String
    Default: db.t2.small
  DBSubnetGroup:
    Description: Group of Subnets used for RDS
    Type: String
  DBPassword:
    Description: Password for RDS
    Type: String
    NoEcho: true
Resources:
  AppTierASG:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
        - !Ref PrivateSubnet1
        - !Ref PrivateSubnet2
      LaunchConfigurationName: !Ref LaunchConfigurationName
      MaxSize: '2'
      MinSize: '2'
      TargetGroupARNs:
        - !Ref LoadBalancerTargetGroup
      Tags:
        - Key: DontParkMe
          Value: "true"
          PropagateAtLaunch: true

  LaunchConfigurationName:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties: 
      ImageId: !Ref AmiId
      SecurityGroups: 
        - !Ref HostSecurityGroup
      InstanceType: !Ref Ec2InstanceType
      KeyName: !Ref SshKey
      UserData:
        Fn::Base64: |
            #!/bin/bash -xe
            # Install Nginx
            sudo amazon-linux-extras install -y nginx1
            # Enable and start service
            sudo systemctl enable nginx
            sudo systemctl start nginx
            sudo sh -c 'echo "<h1>IT WORKS!!!</h1>" > /usr/share/nginx/html/index.html'

  LoadBalancerSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: 'Web Traffic ELB SG'
      VpcId: !Ref VpcID
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0
        # CidrIp: 127.0.0.1/32

  HostSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: 'EC2 ASG Web Tier SG'
      VpcId: !Ref VpcID
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 22
        ToPort: 22
        CidrIp: 10.0.0.0/8
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        # SourceSecurityGroupId: !Ref LoadBalancerSecurityGroup
        # CidrIp: 10.0.0.0/8
        CidrIp: 127.0.0.1/32

  LoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Scheme: internet-facing
      Subnets:
        - !Ref PublicSubnet1
        - !Ref PublicSubnet2
      IpAddressType: ipv4
      SecurityGroups: 
        - !Ref LoadBalancerSecurityGroup

  Listener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      DefaultActions:
        - Type: forward
          TargetGroupArn:
            !Ref LoadBalancerTargetGroup
      LoadBalancerArn:
        !Ref LoadBalancer
      Port: 80
      Protocol: HTTP

  LoadBalancerTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      Port: 80
      Protocol: HTTP
      VpcId: !Ref VpcID
      HealthCheckIntervalSeconds: 30
      HealthCheckPort: '80'
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 10
      HealthyThresholdCount: 3

  DatabaseCluster:
    Type: AWS::RDS::DBCluster
    Properties:
      Engine: aurora
      MasterUsername: 'DemoUser'
      MasterUserPassword: !Ref DBPassword
      DBSubnetGroupName: !Ref DBSubnetGroup
      VpcSecurityGroupIds: 
        - !Ref DBSecurityGroup

  DatabasePrimaryInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      Engine: aurora
      DBClusterIdentifier: !Ref DatabaseCluster
      DBInstanceClass: !Ref DBInstanceType
      DBSubnetGroupName: !Ref DBSubnetGroup

  DatabaseReplicaInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      Engine: aurora
      DBClusterIdentifier: !Ref DatabaseCluster
      DBInstanceClass: !Ref DBInstanceType
      DBSubnetGroupName: !Ref DBSubnetGroup

  DBSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: 'RDS SG'
      VpcId: !Ref VpcID
      SecurityGroupIngress:
      - IpProtocol: tcp
        # FromPort: 3306
        # ToPort: 3306
        FromPort: 306
        ToPort: 306
        SourceSecurityGroupId: !Ref HostSecurityGroup