{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "CoreOS on EC2: http://coreos.com/docs/running-coreos/cloud-providers/ec2/",
  "Mappings" : {
      "RegionMap" : {
          "eu-central-1" : {
              "AMI" : "ami-ffafb293"
          },
          "ap-northeast-1" : {
              "AMI" : "ami-dae8c1b4"
          },
          "us-gov-west-1" : {
              "AMI" : "ami-a98e33c8"
          },
          "sa-east-1" : {
              "AMI" : "ami-4e981c22"
          },
          "ap-southeast-2" : {
              "AMI" : "ami-eeadf58d"
          },
          "ap-southeast-1" : {
              "AMI" : "ami-085a9a6b"
          },
          "us-east-1" : {
              "AMI" : "ami-cbfdb2a1"
          },
          "us-west-2" : {
              "AMI" : "ami-16cfd277"
          },
          "us-west-1" : {
              "AMI" : "ami-0eacc46e"
          },
          "eu-west-1" : {
              "AMI" : "ami-c26bcab1"
          }
      }
  },
  "Parameters": {
    "InstanceType" : {
      "Description" : "EC2 HVM instance type (m3.medium, etc).",
      "Type" : "String",
      "Default" : "t2.medium",
      "AllowedValues" : [ "t2.micro", "m3.medium", "m3.large", "m3.xlarge", "m3.2xlarge", "c3.large","c3.xlarge", "c3.2xlarge", "c3.4xlarge","c3.8xlarge", "cc2.8xlarge","cr1.8xlarge","hi1.4xlarge", "hs1.8xlarge", "i2.xlarge", "i2.2xlarge", "i2.4xlarge", "i2.8xlarge", "r3.large", "r3.xlarge", "r3.2xlarge","r3.4xlarge", "r3.8xlarge", "t2.micro", "t2.small", "t2.medium" ],
      "ConstraintDescription" : "Must be a valid EC2 HVM instance type."
    },
    "SecurityGroupId":{
      "Type": "List<AWS::EC2::SecurityGroup::Id>",
      "Description": "Security group to launch instances into."
    },
    "SubnetId":{
      "Type": "List<AWS::EC2::Subnet::Id>",
      "Description": "VPC group to launch instances into."
    },
    "ClusterSize": {
      "Default": "3",
      "MinValue": "3",
      "MaxValue": "12",
      "Description": "Number of nodes in cluster (3-12).",
      "Type": "Number"
    },
    "DiscoveryURL": {
      "Description": "An unique etcd cluster discovery URL. Grab a new token from https://discovery.etcd.io/new?size=<your cluster size>",
      "Type": "String"
    },
    "AdvertisedIPAddress": {
      "Description": "Use 'private' if your etcd cluster is within one region or 'public' if it spans regions or cloud providers.",
      "Default": "private",
      "AllowedValues": ["private", "public"],
      "Type": "String"
    },
    "KeyPair" : {
      "Description" : "The name of an EC2 Key Pair to allow SSH access to the instance.",
      "Type" : "AWS::EC2::KeyPair::KeyName"
    }
  },
  "Resources": {
    "CoreOSServerAutoScale": {
      "Type": "AWS::AutoScaling::AutoScalingGroup",
      "Properties": {
        "LaunchConfigurationName": {"Ref": "CoreOSServerLaunchConfig"},
        "VPCZoneIdentifier": {"Ref":"SubnetId"},
        "MinSize": "3",
        "MaxSize": "12",
        "DesiredCapacity": {"Ref": "ClusterSize"},
        "Tags": [
            {"Key": "Name", "Value": { "Ref" : "AWS::StackName" }, "PropagateAtLaunch": true}
        ]
      }
    },
    "CoreOSServerLaunchConfig": {
      "Type": "AWS::AutoScaling::LaunchConfiguration",
      "Properties": {
        "ImageId" : { "Fn::FindInMap" : [ "RegionMap", { "Ref" : "AWS::Region" }, "AMI" ]},
        "InstanceType": {"Ref": "InstanceType"},
        "KeyName": {"Ref": "KeyPair"},
        "SecurityGroups": {"Ref": "SecurityGroupId"},
        "UserData" : { "Fn::Base64":
          { "Fn::Join": [ "", [
            "#cloud-config\n\n",
            "coreos:\n",
            "  etcd2:\n",
            "    discovery: ", { "Ref": "DiscoveryURL" }, "\n",
            "    advertise-client-urls: http://$", { "Ref": "AdvertisedIPAddress" }, "_ipv4:2379\n",
            "    initial-advertise-peer-urls: http://$", { "Ref": "AdvertisedIPAddress" }, "_ipv4:2380\n",
            "    listen-client-urls: http://0.0.0.0:2379,http://0.0.0.0:4001\n",
            "    listen-peer-urls: http://$", { "Ref": "AdvertisedIPAddress" }, "_ipv4:2380\n",
            "  units:\n",
            "    - name: etcd2.service\n",
            "      command: start\n",
            "    - name: fleet.service\n",
            "      command: start\n"
            ] ]
          }
        }
      }
    }
  }
}