AWSTemplateFormatVersion: '2010-09-09'
Description: Creates an ECS cluster, consisting of two t2.small instance

Parameters:
  InstanceType:
    Type: String
    Default: t2.small

  ClusterSize:
    Type: Number
    Default: 2

  Subnets:
    Type: List<AWS::EC2::Subnet::Id>

  SourceSecurityGroup1:
    Type: AWS::EC2::SecurityGroup::Id

  SourceSecurityGroup2:
    Type: AWS::EC2::SecurityGroup::Id
    
  VpcId:
    Type: AWS::EC2::VPC::Id

Mappings:
  AWSRegionToAMI:
    us-east-1:
      AMI: ami-04351e12
    us-east-2:
      AMI: ami-207b5a45
    us-west-1:
      AMI: ami-7d664a1d
    us-west-2:
      AMI: ami-57d9cd2e
    eu-west-1:
      AMI: ami-809f84e6
    eu-west-2:
      AMI: ami-ff15039b
    eu-central-1:
      AMI: ami-a3a006cc
    ap-northeast-1:
      AMI: ami-e4657283
    ap-southeast-1:
      AMI: ami-19f7787a
    ap-southeast-2:
      AMI: ami-42e9f921
    ca-central-1:
      AMI: ami-3da81759
    cn-north-1:
      AMI: ami-0de63760

Resources:
  ECSRole:
    Type: AWS::IAM::Role
    Properties:
      Path: /
      AssumeRolePolicyDocument: |
        {
            "Statement": [{
                "Effect": "Allow",
                "Principal": { "Service": [ "ec2.amazonaws.com" ]},
                "Action": [ "sts:AssumeRole" ]
            }]
        }
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role

  InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref ECSRole

  SecurityGroup:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: !Sub ${AWS::StackName}-hosts
      SecurityGroupIngress:
        - SourceSecurityGroupId: !Ref SourceSecurityGroup1
          IpProtocol: -1
        - SourceSecurityGroupId: !Ref SourceSecurityGroup2
          IpProtocol: -1
      VpcId: !Ref VpcId

  Cluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Ref AWS::StackName

  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier: !Ref Subnets
      LaunchConfigurationName: !Ref LaunchConfiguration
      MinSize: 1
      DesiredCapacity: !Ref ClusterSize
      MaxSize: !Ref ClusterSize
      DesiredCapacity: !Ref ClusterSize
      Tags: 
        - Key: Name
          Value: !Sub ${AWS::StackName} - ECS Host
          PropagateAtLaunch: true
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
    UpdatePolicy:
      AutoScalingRollingUpdate:
        MinInstancesInService: 1
        MaxBatchSize: 1
        PauseTime: PT15M
        WaitOnResourceSignals: true

  LaunchConfiguration:
    Type: AWS::AutoScaling::LaunchConfiguration
    Metadata:
      AWS::CloudFormation::Init:
        config:
          commands:
            01_add_instance_to_cluster:
                command: !Sub echo ECS_CLUSTER=${Cluster} > /etc/ecs/ecs.config
          files:
            "/etc/cfn/cfn-hup.conf":
              mode: 000400
              owner: root
              group: root
              content: !Sub |
                [main]
                stack=${AWS::StackId}
                region=${AWS::Region}
            "/etc/cfn/hooks.d/cfn-auto-reloader.conf":
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.ContainerInstances.Metadata.AWS::CloudFormation::Init
                action=/opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource LaunchConfiguration
          services:
            sysvinit:
              cfn-hup:
                enabled: true
                ensureRunning: true
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    Properties:
      ImageId: !FindInMap [ AWSRegionToAMI, !Ref "AWS::Region", AMI ]
      InstanceType: !Ref InstanceType
      IamInstanceProfile: !Ref InstanceProfile
      SecurityGroups:
        - !Ref SecurityGroup
      UserData:
        "Fn::Base64": !Sub |
          #!/bin/bash
          yum install -y aws-cfn-bootstrap
          /opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource LaunchConfiguration
          /opt/aws/bin/cfn-signal -e $? --region ${AWS::Region} --stack ${AWS::StackName} --resource AutoScalingGroup


Outputs:
  ClusterName:
      Value: !Ref Cluster