# Pastebin y0m68xAZ
mwheckmann: {
  "AWSTemplateFormatVersion" : "2010-09-09",
  "Parameters" : {
    "KeyName" : {
      "Description" : "Name of an existing KeyPair to enable SSH access to the instance",
      "Type" : "String"
    },
    "InstanceType" : {
      "Description" : "Instance type",
      "Type" : "String",
      "Default" : "m1.small",
      "AllowedValues" : [ "m1.small" ],
      "ConstraintDescription" : "must be a valid instance type."
    },
    "Image": {
      "Default": "redhat",
      "Description" : "Distribution of choice",
      "Type": "String",
      "AllowedValues" : [ "cirros", "redhat" ]
    },
    "MinPoolSize" : {
      "Default": "1",
      "Description": "Minimum Size of the Scaling Pool",
      "Type": "String"
    },
    "MaxPoolSize" : {
      "Default": "10",
      "Description": "Maximum size of the Scaling Pool",
      "Type": "String"
    }
  },

  "Mappings" : {
    "DistroArch2AMI": {
      "cirros"      : { "64" : "cirros-0.3.1-x86_64" },
      "redhat"      : { "64" : "RedHat_6.4_x86_64" }
    }
  },

  "Resources" : {
    "Nodes" : {
      "Type" : "AWS::AutoScaling::AutoScalingGroup",
      "Properties" : {
        "AvailabilityZones" : { "Fn::GetAZs" : ""},
        "LaunchConfigurationName" : { "Ref" : "LaunchConfig" },
        "MinSize" : { "Ref" : "MinPoolSize" },
        "MaxSize" : { "Ref" : "MaxPoolSize" }
      }
    },
    "LaunchConfig" : {
      "Type" : "AWS::AutoScaling::LaunchConfiguration",
      "Metadata" : {
        "AWS::CloudFormation::Init" : {
          "config" : {
          }
        }
      },
      "Properties" : {
        "KeyName" : { "Ref" : "KeyName" },
        "ImageId" : { "Fn::FindInMap" : [ "DistroArch2AMI", { "Ref" : "Image" }, "64" ] },
        "InstanceType": { "Ref" : "InstanceType" },
        "UserData"  : {
            "Fn::Base64" : {
                "Fn::Join" : ["", [
                    "#!/bin/bash\n", 
                    "if [ -e '/root/setup.sh' ]; then exec /root/setup.sh; fi\n"
                ]]
            }
        }
      }
    },
    "ScaleUpPolicy" : {
      "Type" : "AWS::AutoScaling::ScalingPolicy",
      "Properties" : {
        "AdjustmentType" : "ChangeInCapacity",
        "AutoScalingGroupName" : { "Ref" : "Nodes" },
        "Cooldown" : "60",
        "ScalingAdjustment" : "1"
      }
    },
    "ScaleDownPolicy" : {
      "Type" : "AWS::AutoScaling::ScalingPolicy",
      "Properties" : {
        "AdjustmentType" : "ChangeInCapacity",
        "AutoScalingGroupName" : { "Ref" : "Nodes" },
        "Cooldown" : "60",
        "ScalingAdjustment" : "-1"
      }
    },
    "CPUHighAlarm" : {
        "Type" : "OS::Ceilometer::Alarm",
        "Properties" : {
            "description" : "Scale up with CPU > 80% for 1 minute",
            "meter_name" : "cpu_util",
            "statistic" : "avg",
            "period" : "60",
            "evaluation_periods" : "1",
            "threshold" : "80",
            "alarm_actions" : [ { "Ref" : "ScaleUpPolicy" } ],
            "matching_metadata" : { "metadata.user_metadata.groupname" : { "Ref" : "Nodes" } },
            "comparison_operator" : "gt"
        }
    },
    "CPULowlarm" : {
        "Type" : "OS::Ceilometer::Alarm",
        "Properties" : {
            "description" : "Scale down with CPU < 40% for 5 minute",
            "meter_name" : "cpu_util",
            "statistic" : "avg",
            "period" : "300",
            "evaluation_periods" : "1",
            "threshold" : "40",
            "alarm_actions" : [ { "Ref" : "ScaleDownPolicy" } ],
            "matching_metadata" : { "metadata.user_metadata.groupname" : { "Ref" : "Nodes" } },
            "comparison_operator" : "lt"
        }
    }
  },
  "Outputs" : {
    "ScaleUpTrigger" : {
      "Description" : "Scale Up Policy Trigger",
      "Value" :  { "Fn::Join" : [ "", [ "ScaleUpTrigger=", { "Ref" : "ScaleUpPolicy" } ]] }
    },
    "ScaleDownTrigger" : {
      "Description" : "Scale Dowm Policy Trigger",
      "Value" :  { "Fn::Join" : [ "", [ "ScaleDownTrigger=", { "Ref" : "ScaleDownPolicy" } ]] }
    }
  }
}