{
  "AWSTemplateFormatVersion" : "2010-09-09",
  "Parameters" : {
    "KeyName" : {
      "Description" : "Name of an existing EC2 KeyPair to enable SSH access to the instance",
      "Type" : "String"
    }
  },

  "Resources" : {
    "MyInstance" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "KeyName" : { "Ref" : "KeyName" },
        "ImageId" : "F16-x86_64-cfntools",
        "InstanceType": "m1.large",
        "UserData" : { "Fn::Base64" : "80" }
      }
    }
  },
  "Outputs" : {
    "InstanceIp" : {
      "Value" : { "Fn::Join" : ["", ["ssh ec2-user@",
                                     {"Fn::GetAtt": ["MyInstance",
                                     "PublicIp"]}]]},
      "Description" : "My ssh command"
    }
  }
}