ecs-cluster.yaml

Description: >
  This template deploys an ECS cluster to the provided VPC and subnets
  using an Auto Scaling Group

Parameters:
  EnvironmentName:
    Description: An environment name that will be prefixed to resource names
    Type: String

  InstanceType:
    Description: Which instance type should we use to build the ECS cluster?
    Type: String
    Default: c4.large

  ClusterSize:
    Description: How many ECS hosts do you want to initially deploy?
    Type: Number
    Default: 4

  VPC:
    Description: Choose which VPC this ECS cluster should be deployed to
    Type: AWS::EC2::VPC::Id

  Subnets:
    Description: Choose which subnets this ECS cluster should be deployed to
    Type: List<AWS::EC2::Subnet::Id>

  SecurityGroup:
    Description: Select the Security Group to use for the ECS cluster hosts
    Type: AWS::EC2::SecurityGroup::Id

  ECSAMI:
    Description: ECS-Optimized AMI ID
    Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Default: /aws/service/ecs/optimized-ami/amazon-linux/recommended/image_id

Resources:
  ECSCluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Ref EnvironmentName

  ECSAutoScalingGroup:
    DependsOn: ECSCluster
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier: !Ref Subnets
      LaunchConfigurationName: !Ref ECSLaunchConfiguration
      MinSize: !Ref ClusterSize
      MaxSize: !Ref ClusterSize
      DesiredCapacity: !Ref ClusterSize
      Tags:
        - Key: Name
          Value: !Sub ${EnvironmentName} ECS host
          PropagateAtLaunch: true
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
    UpdatePolicy:
      AutoScalingRollingUpdate:
        MinInstancesInService: 1
        MaxBatchSize: 1
        PauseTime: PT15M
        SuspendProcesses:
          - HealthCheck
          - ReplaceUnhealthy
          - AZRebalance
          - AlarmNotification
          - ScheduledActions
        WaitOnResourceSignals: true

  ECSLaunchConfiguration:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
      ImageId: !Ref ECSAMI
      InstanceType: !Ref InstanceType
      SecurityGroups:
        - !Ref SecurityGroup
      IamInstanceProfile: !Ref ECSInstanceProfile
      UserData:
        "Fn::Base64": !Sub |
          #!/bin/bash
          yum install -y https://s3.amazonaws.com/ec2-downloads-windows/SSMAgent/latest/linux_amd64/amazon-ssm-agent.rpm
          yum install -y https://s3.amazonaws.com/amazoncloudwatch-agent/amazon_linux/amd64/latest/amazon-cloudwatch-agent.rpm
          yum install -y aws-cfn-bootstrap hibagent 
          /opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource ECSLaunchConfiguration
          /opt/aws/bin/cfn-signal -e $? --region ${AWS::Region} --stack ${AWS::StackName} --resource ECSAutoScalingGroup
          /usr/bin/enable-ec2-spot-hibernation

    Metadata:
      AWS::CloudFormation::Init:
        config:
          packages:
            yum:
              collectd: []

          commands:
            01_add_instance_to_cluster:
              command: !Sub echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
            02_enable_cloudwatch_agent:
              command: !Sub /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c ssm:${ECSCloudWatchParameter} -s
          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.ECSLaunchConfiguration.Metadata.AWS::CloudFormation::Init
                action=/opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource ECSLaunchConfiguration

          services:
            sysvinit:
              cfn-hup:
                enabled: true
                ensureRunning: true
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf

  # This IAM Role is attached to all of the ECS hosts. It is based on the default role
  # published here:
  # http://docs.aws.amazon.com/AmazonECS/latest/developerguide/instance_IAM_role.html
  #
  # You can add other IAM policy statements here to allow access from your ECS hosts
  # to other AWS services. Please note that this role will be used by ALL containers
  # running on the ECS host.

  ECSRole:
    Type: AWS::IAM::Role
    Properties:
      Path: /
      RoleName: !Sub ${EnvironmentName}-ECSRole-${AWS::Region}
      AssumeRolePolicyDocument: |
        {
            "Statement": [{
                "Action": "sts:AssumeRole",
                "Effect": "Allow",
                "Principal": {
                    "Service": "ec2.amazonaws.com"
                }
            }]
        }
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonEC2RoleforSSM
        - arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy
      Policies:
        - PolicyName: ecs-service
          PolicyDocument: |
            {
                "Statement": [{
                    "Effect": "Allow",
                    "Action": [
                        "ecs:CreateCluster",
                        "ecs:DeregisterContainerInstance",
                        "ecs:DiscoverPollEndpoint",
                        "ecs:Poll",
                        "ecs:RegisterContainerInstance",
                        "ecs:StartTelemetrySession",
                        "ecs:Submit*",
                        "ecr:BatchCheckLayerAvailability",
                        "ecr:BatchGetImage",
                        "ecr:GetDownloadUrlForLayer",
                        "ecr:GetAuthorizationToken"
                    ],
                    "Resource": "*"
                }]
            }

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

  ECSServiceAutoScalingRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          Action:
            - "sts:AssumeRole"
          Effect: Allow
          Principal:
            Service:
              - application-autoscaling.amazonaws.com
      Path: /
      Policies:
        - PolicyName: ecs-service-autoscaling
          PolicyDocument:
            Statement:
              Effect: Allow
              Action:
                - application-autoscaling:*
                - cloudwatch:DescribeAlarms
                - cloudwatch:PutMetricAlarm
                - ecs:DescribeServices
                - ecs:UpdateService
              Resource: "*"

  ECSCloudWatchParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Description: ECS
      Name: !Sub "AmazonCloudWatch-${ECSCluster}-ECS"
      Type: String
      Value: !Sub |
        {
          "logs": {
            "force_flush_interval": 5,
            "logs_collected": {
              "files": {
                "collect_list": [
                  {
                    "file_path": "/var/log/messages",
                    "log_group_name": "${ECSCluster}-/var/log/messages",
                    "log_stream_name": "{instance_id}",
                    "timestamp_format": "%b %d %H:%M:%S"
                  },
                  {
                    "file_path": "/var/log/dmesg",
                    "log_group_name": "${ECSCluster}-/var/log/dmesg",
                    "log_stream_name": "{instance_id}"
                  },
                  {
                    "file_path": "/var/log/docker",
                    "log_group_name": "${ECSCluster}-/var/log/docker",
                    "log_stream_name": "{instance_id}",
                    "timestamp_format": "%Y-%m-%dT%H:%M:%S.%f"
                  },
                  {
                    "file_path": "/var/log/ecs/ecs-init.log",
                    "log_group_name": "${ECSCluster}-/var/log/ecs/ecs-init.log",
                    "log_stream_name": "{instance_id}",
                    "timestamp_format": "%Y-%m-%dT%H:%M:%SZ"
                  },
                  {
                    "file_path": "/var/log/ecs/ecs-agent.log.*",
                    "log_group_name": "${ECSCluster}-/var/log/ecs/ecs-agent.log",
                    "log_stream_name": "{instance_id}",
                    "timestamp_format": "%Y-%m-%dT%H:%M:%SZ"
                  },
                  {
                    "file_path": "/var/log/ecs/audit.log",
                    "log_group_name": "${ECSCluster}-/var/log/ecs/audit.log",
                    "log_stream_name": "{instance_id}",
                    "timestamp_format": "%Y-%m-%dT%H:%M:%SZ"
                  }
                ]
              }
            }
          },
          "metrics": {
            "append_dimensions": {
              "AutoScalingGroupName": "${!aws:AutoScalingGroupName}",
              "InstanceId": "${!aws:InstanceId}",
              "InstanceType": "${!aws:InstanceType}"
            },
            "metrics_collected": {
              "collectd": {
                "metrics_aggregation_interval": 60
              },
              "disk": {
                "measurement": [
                  "used_percent"
                ],
                "metrics_collection_interval": 60,
                "resources": [
                  "/"
                ]
              },
              "mem": {
                "measurement": [
                  "mem_used_percent"
                ],
                "metrics_collection_interval": 60
              },
              "statsd": {
                "metrics_aggregation_interval": 60,
                "metrics_collection_interval": 10,
                "service_address": ":8125"
              }
            }
          }
        }

Outputs:
  Cluster:
    Description: A reference to the ECS cluster
    Value: !Ref ECSCluster

  ECSServiceAutoScalingRole:
    Description: A reference to ECS service auto scaling role
    Value: !GetAtt ECSServiceAutoScalingRole.Arn

  ECSAutoScalingGroupName:
    Description: A reference to ECS AutoScaling Group Name
    Value: !Ref ECSAutoScalingGroup