AWSTemplateFormatVersion: 2010-09-09
Parameters:
  KeyName:
    Type: 'AWS::EC2::KeyPair::KeyName'
    Description: Name of an existing EC2 KeyPair to enable SSH access to the ECS instances.
  VpcId:
    Type: 'AWS::EC2::VPC::Id'
    Description: Select a VPC that allows instances to access the Internet.
  SubnetId:
    Type: 'List<AWS::EC2::Subnet::Id>'
    Description: Select at two subnets in your selected VPC.
  DesiredCapacity:
    Type: Number
    Default: '1'
    Description: Number of instances to launch in your ECS cluster.
  MaxSize:
    Type: Number
    Default: '1'
    Description: Maximum number of instances that can be launched in your ECS cluster.
  PolicyTargetValue:
    Type: Number
    Default: '80'
  InstanceType:
    Description: EC2 instance type
    Type: String
    Default: t2.micro
    AllowedValues:
      - t2.micro
      - t2.small
      - t2.medium
      - t2.large
      - m3.medium
      - m3.large
      - m3.xlarge
      - m3.2xlarge
      - m4.large
      - m4.xlarge
      - m4.2xlarge
      - m4.4xlarge
      - m4.10xlarge
      - c4.large
      - c4.xlarge
      - c4.2xlarge
      - c4.4xlarge
      - c4.8xlarge
      - c3.large
      - c3.xlarge
      - c3.2xlarge
      - c3.4xlarge
      - c3.8xlarge
      - r3.large
      - r3.xlarge
      - r3.2xlarge
      - r3.4xlarge
      - r3.8xlarge
      - i2.xlarge
      - i2.2xlarge
      - i2.4xlarge
      - i2.8xlarge
    ConstraintDescription: Please choose a valid instance type.
Mappings:
  AWSRegionToAMI:
    us-east-1:
      AMIID: ami-5253c32d
    us-east-2:
      AMIID: ami-446f3521
    us-west-1:
      AMIID: ami-9fadf8ff
    us-west-2:
      AMIID: ami-7abc111a
    eu-west-1:
      AMIID: ami-a1491ad2
    eu-central-1:
      AMIID: ami-54f5303b
    ap-northeast-1:
      AMIID: ami-9cd57ffd
    ap-southeast-1:
      AMIID: ami-a900a3ca
    ap-southeast-2:
      AMIID: ami-5781be34
Resources:
  ECSCluster:
    Type: 'AWS::ECS::Cluster'
  EcsSecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: ECS Security Group
      VpcId: !Ref VpcId
  EcsSecurityGroupHTTPinbound:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Properties:
      GroupId: !Ref EcsSecurityGroup
      IpProtocol: tcp
      FromPort: '80'
      ToPort: '80'
      CidrIp: 0.0.0.0/0
  EcsSecurityGroupSSHinbound:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Properties:
      GroupId: !Ref EcsSecurityGroup
      IpProtocol: tcp
      FromPort: '22'
      ToPort: '22'
      CidrIp: 0.0.0.0/0
  EcsSecurityGroupALBports:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Properties:
      GroupId: !Ref EcsSecurityGroup
      IpProtocol: tcp
      FromPort: '31000'
      ToPort: '61000'
      SourceSecurityGroupId: !Ref EcsSecurityGroup
  CloudwatchLogsGroup:
    Type: 'AWS::Logs::LogGroup'
    Properties:
      LogGroupName: !Join 
        - '-'
        - - ECSLogGroup
          - !Ref 'AWS::StackName'
      RetentionInDays: 14
  taskdefinition:
    Type: 'AWS::ECS::TaskDefinition'
    Properties:
      Family: !Join 
        - ''
        - - !Ref 'AWS::StackName'
          - '-ecs-demo-app'
      ContainerDefinitions:
        - Name: simple-app
          Cpu: '10'
          Essential: 'true'
          Image: 415946555495.dkr.ecr.ap-southeast-1.amazonaws.com/ecsci
          Memory: '300'
          LogConfiguration:
            LogDriver: awslogs
            Options:
              awslogs-group: !Ref CloudwatchLogsGroup
              awslogs-region: !Ref 'AWS::Region'
              awslogs-stream-prefix: ecs-demo-app
          PortMappings:
            - ContainerPort: 80
  ECSALB:
    Type: 'AWS::ElasticLoadBalancingV2::LoadBalancer'
    Properties:
      Name: ECSALB
      Scheme: internet-facing
      LoadBalancerAttributes:
        - Key: idle_timeout.timeout_seconds
          Value: '30'
      Subnets: !Ref SubnetId
      SecurityGroups:
        - !Ref EcsSecurityGroup
  ALBListener:
    Type: 'AWS::ElasticLoadBalancingV2::Listener'
    DependsOn: ECSServiceRole
    Properties:
      DefaultActions:
        - Type: forward
          TargetGroupArn: !Ref ECSTG
      LoadBalancerArn: !Ref ECSALB
      Port: '80'
      Protocol: HTTP
  ECSALBListenerRule:
    Type: 'AWS::ElasticLoadBalancingV2::ListenerRule'
    DependsOn: ALBListener
    Properties:
      Actions:
        - Type: forward
          TargetGroupArn: !Ref ECSTG
      Conditions:
        - Field: path-pattern
          Values:
            - /
      ListenerArn: !Ref ALBListener
      Priority: 1
  ECSTG:
    Type: 'AWS::ElasticLoadBalancingV2::TargetGroup'
    DependsOn: ECSALB
    Properties:
      HealthCheckIntervalSeconds: 10
      HealthCheckPath: /
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 5
      HealthyThresholdCount: 2
      Name: ECSTG
      Port: 80
      Protocol: HTTP
      UnhealthyThresholdCount: 2
      VpcId: !Ref VpcId
  ECSAutoScalingGroup:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      VPCZoneIdentifier: !Ref SubnetId
      LaunchConfigurationName: !Ref ContainerInstances
      MinSize: '1'
      MaxSize: !Ref MaxSize
      DesiredCapacity: !Ref DesiredCapacity
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
    UpdatePolicy:
      AutoScalingReplacingUpdate:
        WillReplace: 'true'
  ScalingPolicy:
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AutoScalingGroupName: !Ref ECSAutoScalingGroup
      PolicyType: TargetTrackingScaling
      TargetTrackingConfiguration:
        PredefinedMetricSpecification:
          PredefinedMetricType: ASGAverageCPUUtilization
        TargetValue: !Ref PolicyTargetValue
  ContainerInstances:
    Type: 'AWS::AutoScaling::LaunchConfiguration'
    Properties:
      ImageId: !FindInMap 
        - AWSRegionToAMI
        - !Ref 'AWS::Region'
        - AMIID
      SecurityGroups:
        - !Ref EcsSecurityGroup
      InstanceType: !Ref InstanceType
      IamInstanceProfile: !Ref EC2InstanceProfile
      KeyName: !Ref KeyName
      UserData: !Base64 
        'Fn::Join':
          - ''
          - - |
              #!/bin/bash -xe
            - echo ECS_CLUSTER=
            - !Ref ECSCluster
            - |2
               >> /etc/ecs/ecs.config
            - |
              yum install -y aws-cfn-bootstrap
            - '/opt/aws/bin/cfn-signal -e $? '
            - '         --stack '
            - !Ref 'AWS::StackName'
            - '         --resource ECSAutoScalingGroup '
            - '         --region '
            - !Ref 'AWS::Region'
            - |+

  service:
    Type: 'AWS::ECS::Service'
    DependsOn: ALBListener
    Properties:
      Cluster: !Ref ECSCluster
      DesiredCount: '1'
      LoadBalancers:
        - ContainerName: simple-app
          ContainerPort: '80'
          TargetGroupArn: !Ref ECSTG
      Role: !Ref ECSServiceRole
      TaskDefinition: !Ref taskdefinition
  ECSServiceRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ecs.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: ecs-service
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - 'elasticloadbalancing:DeregisterInstancesFromLoadBalancer'
                  - 'elasticloadbalancing:DeregisterTargets'
                  - 'elasticloadbalancing:Describe*'
                  - 'elasticloadbalancing:RegisterInstancesWithLoadBalancer'
                  - 'elasticloadbalancing:RegisterTargets'
                  - 'ec2:Describe*'
                  - 'ec2:AuthorizeSecurityGroupIngress'
                Resource: '*'
  ServiceScalingTarget:
    Type: 'AWS::ApplicationAutoScaling::ScalableTarget'
    DependsOn: service
    Properties:
      MaxCapacity: 2
      MinCapacity: 1
      ResourceId: !Join 
        - ''
        - - service/
          - !Ref ECSCluster
          - /
          - !GetAtt 
            - service
            - Name
      RoleARN: !GetAtt 
        - AutoscalingRole
        - Arn
      ScalableDimension: 'ecs:service:DesiredCount'
      ServiceNamespace: ecs
  ServiceScalingPolicy:
    Type: 'AWS::ApplicationAutoScaling::ScalingPolicy'
    Properties:
      PolicyName: AStepPolicy
      PolicyType: StepScaling
      ScalingTargetId: !Ref ServiceScalingTarget
      StepScalingPolicyConfiguration:
        AdjustmentType: PercentChangeInCapacity
        Cooldown: 60
        MetricAggregationType: Average
        StepAdjustments:
          - MetricIntervalLowerBound: 0
            ScalingAdjustment: 200
  ALB500sAlarmScaleUp:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      EvaluationPeriods: '1'
      Statistic: Average
      Threshold: '10'
      AlarmDescription: Alarm if our ALB generates too many HTTP 500s.
      Period: '60'
      AlarmActions:
        - !Ref ServiceScalingPolicy
      Namespace: AWS/ApplicationELB
      Dimensions:
        - Name: LoadBalancer
          Value: !GetAtt 
            - ECSALB
            - LoadBalancerFullName
      ComparisonOperator: GreaterThanThreshold
      MetricName: HTTPCode_ELB_5XX_Count
  EC2Role:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: ecs-service
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - 'ecs:CreateCluster'
                  - 'ecs:DeregisterContainerInstance'
                  - 'ecs:DiscoverPollEndpoint'
                  - 'ecs:Poll'
                  - 'ecs:RegisterContainerInstance'
                  - 'ecs:StartTelemetrySession'
                  - 'ecs:Submit*'
                  - 'logs:CreateLogStream'
                  - 'logs:PutLogEvents'
                  - 'ecr:*'
                  - 'cloudtrail:LookupEvents'
                Resource: '*'
  AutoscalingRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - application-autoscaling.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: service-autoscaling
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - 'application-autoscaling:*'
                  - 'cloudwatch:DescribeAlarms'
                  - 'cloudwatch:PutMetricAlarm'
                  - 'ecs:DescribeServices'
                  - 'ecs:UpdateService'
                Resource: '*'
  EC2InstanceProfile:
    Type: 'AWS::IAM::InstanceProfile'
    Properties:
      Path: /
      Roles:
        - !Ref EC2Role
Outputs:
  ecsservice:
    Value: !Ref service
  ecscluster:
    Value: !Ref ECSCluster
  ECSALB:
    Description: Your ALB DNS URL
    Value: !Join 
      - ''
      - - !GetAtt 
          - ECSALB
          - DNSName
  taskdef:
    Value: !Ref taskdefinition