BuildHost spec

   "BuildServer" : {
      "Type" : "AWS::EC2::Instance",
      "DependsOn" : "AttachGateway",
      "Metadata" : {
        "AWS::CloudFormation::Init" : {
          "config" : {
            "sources" : {
              "/root" : "https://github.com/bryantrobbins/standard-aws/tarball/master"
            },
            "files" : {
              "/root/init/datadir/custom.yaml" : {
                "content" : { "Ref": "Hieradata"},
                "encoding": "base64",
                "mode"  : "000644",
                "owner" : "root",
                "group" : "root"
              }
            },
            "commands" : {
              "init-script" : {
                "command" : "bash -x init.sh build &> /var/log/init.log", 
                "cwd" : "/root/init"
              }
            }
          }
        }
      },
      "Properties" : {
        "ImageId" : { "Fn::FindInMap" : [ "AWSRegionArch2AMI", { "Ref" : "AWS::Region" },
                          { "Fn::FindInMap" : [ "AWSInstanceType2Arch", { "Ref" : "BuildInstanceType" }, "Arch" ] } ] },
        "InstanceType" : { "Ref" : "BuildInstanceType" },
        "KeyName" : { "Ref" : "KeyName" },
        "IamInstanceProfile": {
          "Ref": "DeployInstanceProfile"
        },
        "NetworkInterfaces" : [{
          "GroupSet"                 : [{ "Ref" : "SecurityGroupInternetSSH" }, { "Ref" : "SecurityGroupWebService" }, { "Ref": "ConsulServerSecurityGroup" }, { "Ref": "ConsulAgentSecurityGroup" }, { "Ref": "CommonSecurityGroup" }],
          "AssociatePublicIpAddress" : "true",
          "DeviceIndex"              : "0",
          "DeleteOnTermination"      : "true",
          "SubnetId"                 : { "Ref" : "Subnet" }
        }],
        "UserData" : { "Fn::Base64" : { "Fn::Join" : ["", [
          "#!/bin/bash -xe\n",
          "yum update -y aws-cfn-bootstrap\n",
          "/opt/aws/bin/cfn-init ",
          " --stack ", { "Ref" : "AWS::StackName" },
          " --resource BuildServer ",
          " --region ", { "Ref" : "AWS::Region" }, "\n"
        ]]}}
      }
    },