AWSTemplateFormatVersion: 2010-09-09
Description: >-
  AWS CloudFormation Sample Template. Create a multi-az, load balanced and auto-scaled 
  sample web site running on an Apache Web Server. The application is configured to span all Availability Zones in
  the region and is auto-scaled based on the CPU utilization of the web servers.
  Notifications will be sent to the operator email address on scaling events.
  The instances are load balanced with a simple health check against the default
  web page. **WARNING** This template creates one or more Amazon EC2 instances
  and an Elastic Load Balancer. You will be billed for the AWS resources used if
  you create a stack from this template.
Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
    - Label:
        default: Network configuration
      Parameters:
      - VPCID
      - PrivateSubnet1ID
      - PrivateSubnet2ID
      - PublicSubnet1ID
      - PublicSubnet2ID
    - Label:
        default: Workload nodes configuration
      Parameters:
      - KeyName
      - InstanceType
      - SSHLocation
      - OperatorEMail
      - EnvType
    
    ParameterLabels:
      KeyName:
        default: SSH key name
      OperatorEMail:
        default: Operator email
      PrivateSubnet1ID:
        default: Private subnet 1 ID
      PrivateSubnet2ID:
        default: Private subnet 2 ID
      PublicSubnet1ID:
        default: Public subnet 1 ID
      PublicSubnet2ID:
        default: Public subnet 2 ID
      VPCID:
        default: VPC ID
      InstanceType:
        default: Workload servers instance type
      SSHLocation:
        default: Workload nodes SSH CIDR Block
      EnvType:
        default: Envrionment type

Parameters:
  InstanceType:
    Description: WebServer EC2 instance type
    Type: String
    Default: t2.small
    AllowedValues:
      - t1.micro
      - t2.nano
      - t2.micro
      - t2.small
      - t2.medium
      - t2.large
      - m1.small
      - m1.medium
      - m1.large
      - m1.xlarge
      - m2.xlarge
      - m2.2xlarge
      - m2.4xlarge
      - m3.medium
      - m3.large
      - m3.xlarge
      - m3.2xlarge
      - m4.large
      - m4.xlarge
      - m4.2xlarge
      - m4.4xlarge
      - m4.10xlarge
      - c1.medium
      - c1.xlarge
      - c3.large
      - c3.xlarge
      - c3.2xlarge
      - c3.4xlarge
      - c3.8xlarge
      - c4.large
      - c4.xlarge
      - c4.2xlarge
      - c4.4xlarge
      - c4.8xlarge
      - g2.2xlarge
      - g2.8xlarge
      - r3.large
      - r3.xlarge
      - r3.2xlarge
      - r3.4xlarge
      - r3.8xlarge
      - i2.xlarge
      - i2.2xlarge
      - i2.4xlarge
      - i2.8xlarge
      - d2.xlarge
      - d2.2xlarge
      - d2.4xlarge
      - d2.8xlarge
      - hi1.4xlarge
      - hs1.8xlarge
      - cr1.8xlarge
      - cc2.8xlarge
      - cg1.4xlarge
    ConstraintDescription: must be a valid EC2 instance type.
  OperatorEMail:
    Description: EMail address to notify if there are any scaling operations
    Type: String
    AllowedPattern: >-
      ([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)
    ConstraintDescription: must be a valid email address.
  KeyName:
    Description: The EC2 Key Pair to allow SSH access to the instances
    Type: 'AWS::EC2::KeyPair::KeyName'
    ConstraintDescription: must be the name of an existing EC2 KeyPair.
  SSHLocation:
    Description: The IP address range that can be used to SSH to the EC2 instances
    Type: String
    MinLength: '9'
    MaxLength: '18'
    Default: 0.0.0.0/0
    AllowedPattern: '(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/(\d{1,2})'
    ConstraintDescription: must be a valid IP CIDR range of the form x.x.x.x/x.
  PrivateSubnet1ID:
    Description: Private Subnet Id 1
    Type: 'AWS::EC2::Subnet::Id'
  PrivateSubnet2ID:
    Description: Private Subnet Id 2
    Type: 'AWS::EC2::Subnet::Id'
  PublicSubnet1ID:
    Description: Public Subnet Id 1
    Type: 'AWS::EC2::Subnet::Id'
  PublicSubnet2ID:
    Description: Public Subnet Id 2
    Type: 'AWS::EC2::Subnet::Id'
  VPCID:
    Description: 'ID of the VPC (e.g., vpc-0343606e)'
    Type: 'AWS::EC2::VPC::Id'
  EnvType:
    Description: 'Environment type'
    Type: String
    Default: Dev
    AllowedValues:
      - Dev
      - Prod

Conditions:
  CreateProdResources: !Equals 
    - !Ref EnvType
    - Prod

Mappings:
  AWSInstanceType2Arch:
    t1.micro:
      Arch: HVM64
    t2.nano:
      Arch: HVM64
    t2.micro:
      Arch: HVM64
    t2.small:
      Arch: HVM64
    t2.medium:
      Arch: HVM64
    t2.large:
      Arch: HVM64
    m1.small:
      Arch: HVM64
    m1.medium:
      Arch: HVM64
    m1.large:
      Arch: HVM64
    m1.xlarge:
      Arch: HVM64
    m2.xlarge:
      Arch: HVM64
    m2.2xlarge:
      Arch: HVM64
    m2.4xlarge:
      Arch: HVM64
    m3.medium:
      Arch: HVM64
    m3.large:
      Arch: HVM64
    m3.xlarge:
      Arch: HVM64
    m3.2xlarge:
      Arch: HVM64
    m4.large:
      Arch: HVM64
    m4.xlarge:
      Arch: HVM64
    m4.2xlarge:
      Arch: HVM64
    m4.4xlarge:
      Arch: HVM64
    m4.10xlarge:
      Arch: HVM64
    c1.medium:
      Arch: HVM64
    c1.xlarge:
      Arch: HVM64
    c3.large:
      Arch: HVM64
    c3.xlarge:
      Arch: HVM64
    c3.2xlarge:
      Arch: HVM64
    c3.4xlarge:
      Arch: HVM64
    c3.8xlarge:
      Arch: HVM64
    c4.large:
      Arch: HVM64
    c4.xlarge:
      Arch: HVM64
    c4.2xlarge:
      Arch: HVM64
    c4.4xlarge:
      Arch: HVM64
    c4.8xlarge:
      Arch: HVM64
    g2.2xlarge:
      Arch: HVMG2
    g2.8xlarge:
      Arch: HVMG2
    r3.large:
      Arch: HVM64
    r3.xlarge:
      Arch: HVM64
    r3.2xlarge:
      Arch: HVM64
    r3.4xlarge:
      Arch: HVM64
    r3.8xlarge:
      Arch: HVM64
    i2.xlarge:
      Arch: HVM64
    i2.2xlarge:
      Arch: HVM64
    i2.4xlarge:
      Arch: HVM64
    i2.8xlarge:
      Arch: HVM64
    d2.xlarge:
      Arch: HVM64
    d2.2xlarge:
      Arch: HVM64
    d2.4xlarge:
      Arch: HVM64
    d2.8xlarge:
      Arch: HVM64
    hi1.4xlarge:
      Arch: HVM64
    hs1.8xlarge:
      Arch: HVM64
    cr1.8xlarge:
      Arch: HVM64
    cc2.8xlarge:
      Arch: HVM64
  AWSRegionArch2AMI:
    us-east-1:
      HVM64: ami-0ff8a91507f77f867
    us-west-2:
      HVM64: ami-a0cfeed8
    us-west-1:
      HVM64: ami-0bdb828fd58c52235
    eu-west-1:
      HVM64: ami-047bb4163c506cd98
    eu-west-2:
      HVM64: ami-f976839e
    eu-west-3:
      HVM64: ami-0ebc281c20e89ba4b
    eu-central-1:
      HVM64: ami-0233214e13e500f77
    ap-northeast-1:
      HVM64: ami-06cd52961ce9f0d85
    ap-northeast-2:
      HVM64: ami-0a10b2721688ce9d2
    ap-northeast-3:
      HVM64: ami-0d98120a9fb693f07
    ap-southeast-1:
      HVM64: ami-08569b978cc4dfa10
    ap-southeast-2:
      HVM64: ami-09b42976632b27e9b
    ap-south-1:
      HVM64: ami-0912f71e06545ad88
    us-east-2:
      HVM64: ami-0b59bfac6be064b78
    ca-central-1:
      HVM64: ami-0b18956f
    sa-east-1:
      HVM64: ami-07b14488da8ea02a0
    cn-north-1:
      HVM64: ami-0a4eaf6c4454eda75
    cn-northwest-1:
      HVM64: ami-6b6a7d09
      
Resources:
  NotificationTopic:
    Type: 'AWS::SNS::Topic'
    Properties:
      Subscription:
        - Endpoint: !Ref OperatorEMail
          Protocol: email
  WebServerGroup:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      VPCZoneIdentifier:
        - !Ref PrivateSubnet1ID
        - !Ref PrivateSubnet2ID
      LaunchConfigurationName: !Ref LaunchConfig
      MinSize: '1'
      MaxSize: '3'
      LoadBalancerNames:
        - !Ref ElasticLoadBalancer
      NotificationConfiguration:
        TopicARN: !Ref NotificationTopic
        NotificationTypes:
          - 'autoscaling:EC2_INSTANCE_LAUNCH'
          - 'autoscaling:EC2_INSTANCE_LAUNCH_ERROR'
          - 'autoscaling:EC2_INSTANCE_TERMINATE'
          - 'autoscaling:EC2_INSTANCE_TERMINATE_ERROR'
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
        Count: '1'
    UpdatePolicy:
      AutoScalingRollingUpdate:
        MinInstancesInService: '1'
        MaxBatchSize: '1'
        PauseTime: PT15M
        WaitOnResourceSignals: 'true'
  LaunchConfig:
    Type: 'AWS::AutoScaling::LaunchConfiguration'
    Metadata:
      Comment: Install a simple application
      'AWS::CloudFormation::Init':
        config:
          packages:
            yum:
              httpd: []
          files:
            /var/www/html/index.html:
              content: !Join 
                - |+

                - - >-
                    <h1>Congratulations, you have successfully launched the AWS
                    CloudFormation sample.</h1>
              mode: '000644'
              owner: root
              group: root
            /etc/cfn/cfn-hup.conf:
              content: !Join 
                - ''
                - - |
                    [main]
                  - stack=
                  - !Ref 'AWS::StackId'
                  - |+

                  - region=
                  - !Ref 'AWS::Region'
                  - |+

              mode: '000400'
              owner: root
              group: root
            /etc/cfn/hooks.d/cfn-auto-reloader.conf:
              content: !Join 
                - ''
                - - |
                    [cfn-auto-reloader-hook]
                  - |
                    triggers=post.update
                  - >
                    path=Resources.LaunchConfig.Metadata.AWS::CloudFormation::Init
                  - 'action=/opt/aws/bin/cfn-init -v '
                  - '         --stack '
                  - !Ref 'AWS::StackName'
                  - '         --resource LaunchConfig '
                  - '         --region '
                  - !Ref 'AWS::Region'
                  - |+

                  - |
                    runas=root
          services:
            sysvinit:
              httpd:
                enabled: 'true'
                ensureRunning: 'true'
              cfn-hup:
                enabled: 'true'
                ensureRunning: 'true'
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    Properties:
      KeyName: !Ref KeyName
      ImageId: !FindInMap 
        - AWSRegionArch2AMI
        - !Ref 'AWS::Region'
        - !FindInMap 
          - AWSInstanceType2Arch
          - !Ref InstanceType
          - Arch
      SecurityGroups:
        - !GetAtt InstanceSecurityGroup.GroupId
      InstanceType: !Ref InstanceType
      UserData: !Base64 
        'Fn::Join':
          - ''
          - - |
              #!/bin/bash -xe
            - |
              yum update -y aws-cfn-bootstrap
            - '/opt/aws/bin/cfn-init -v '
            - '         --stack '
            - !Ref 'AWS::StackName'
            - '         --resource LaunchConfig '
            - '         --region '
            - !Ref 'AWS::Region'
            - |+

            - '/opt/aws/bin/cfn-signal -e $? '
            - '         --stack '
            - !Ref 'AWS::StackName'
            - '         --resource WebServerGroup '
            - '         --region '
            - !Ref 'AWS::Region'
            - |+

  WebServerScaleUpPolicy:
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref WebServerGroup
      Cooldown: '60'
      ScalingAdjustment: '1'
  WebServerScaleDownPolicy:
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref WebServerGroup
      Cooldown: '60'
      ScalingAdjustment: '-1'
  CPUAlarmHigh:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmDescription: Scale-up if CPU > 90% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '2'
      Threshold: '90'
      AlarmActions:
        - !Ref WebServerScaleUpPolicy
      Dimensions:
        - Name: AutoScalingGroupName
          Value: !Ref WebServerGroup
      ComparisonOperator: GreaterThanThreshold
  CPUAlarmLow:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmDescription: Scale-down if CPU < 70% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '2'
      Threshold: '70'
      AlarmActions:
        - !Ref WebServerScaleDownPolicy
      Dimensions:
        - Name: AutoScalingGroupName
          Value: !Ref WebServerGroup
      ComparisonOperator: LessThanThreshold
  ElasticLoadBalancer:
    Type: 'AWS::ElasticLoadBalancing::LoadBalancer'
    Properties:
      Subnets:
        - !Ref PublicSubnet1ID
        - !Ref PublicSubnet2ID
      CrossZone: 'true'
      Listeners:
        - LoadBalancerPort: '80'
          InstancePort: '80'
          Protocol: HTTP
      HealthCheck:
        Target: 'HTTP:80/'
        HealthyThreshold: '3'
        UnhealthyThreshold: '5'
        Interval: '30'
        Timeout: '5'
      SecurityGroups:
        - !GetAtt LoadBalancerSecurityGroup.GroupId
  InstanceSecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: Enable SSH access and HTTP from the load balancer only
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: !Ref SSHLocation
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          SourceSecurityGroupId: !GetAtt LoadBalancerSecurityGroup.GroupId
      VpcId: !Ref VPCID
  LoadBalancerSecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: Enable HTTP from the world
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0
      VpcId: !Ref VPCID
  ProdLoadBalancerSecurityGroup:
    Condition: CreateProdResources
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: Enable HTTP from the world
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 443
          ToPort: 443
          CidrIp: 0.0.0.0/0
      VpcId: !Ref VPCID
Outputs:
  URL:
    Description: The URL of the website
    Value: !Join 
      - ''
      - - 'http://'
        - !GetAtt 
          - ElasticLoadBalancer
          - DNSName