{
  "AWSTemplateFormatVersion" : "2010-09-09",

  "Description" : "AWS CloudFormation Sample Template UpdateTutorial Part 5: Sample template that can be used to test EC2 updates convert a single instance deployment into an Auto Scaled, Load Balanced solutio. **WARNING** This template creates an Amazon Ec2 Instance. You will be billed for the AWS resources used if you create a stack from this template.",
  
  "Parameters" : {

    "WebServerKeyName" : {
      "Description" : "Name of an existing Amazon EC2 KeyPair for SSH access",
      "Type" : "String"
    },
          
    "WebServerInstanceType" : {
      "Description" : "WebServer EC2 instance type",
      "Type" : "String",
      "Default" : "m1.small",
      "AllowedValues" : [ "t1.micro","m1.small","m1.medium","m1.large","m1.xlarge","m2.xlarge","m2.2xlarge","m2.4xlarge","m3.xlarge","m3.2xlarge","c1.medium","c1.xlarge","cc1.4xlarge","cc2.8xlarge","cg1.4xlarge"],
      "ConstraintDescription" : "must be a valid EC2 instance type."
    },
    "SSHLocation" : {
      "Description" : " The IP address range that can be used to SSH to the EC2 instances",
      "Type": "String",
      "MinLength": "9",
      "MaxLength": "18",
      "Default": "0.0.0.0/0",
      "AllowedPattern": "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})/(\\d{1,2})",
      "ConstraintDescription": "must be a valid IP CIDR range of the form x.x.x.x/x."
    }  
  },
  
  "Mappings" : {
    "AWSInstanceType2Arch" : {
      "t1.micro"    : { "Arch" : "32" },
      "m1.small"    : { "Arch" : "32" },
      "m1.medium"   : { "Arch" : "64" },
      "m1.large"    : { "Arch" : "64" },
      "m1.xlarge"   : { "Arch" : "64" },
      "m2.xlarge"   : { "Arch" : "64" },
      "m2.2xlarge"  : { "Arch" : "64" },
      "m2.4xlarge"  : { "Arch" : "64" },
      "m3.xlarge"   : { "Arch" : "64" },
      "m3.2xlarge"  : { "Arch" : "64" },
      "c1.medium"   : { "Arch" : "64" },
      "c1.xlarge"   : { "Arch" : "64" },
      "cc1.4xlarge" : { "Arch" : "64HVM" },
      "cc2.8xlarge" : { "Arch" : "64HVM" },
      "cg1.4xlarge" : { "Arch" : "64HVM" }
    },

    "AWSRegionArch2AMI" : {
      "us-east-1"      : { "32" : "ami-31814f58", "64" : "ami-1b814f72", "64HVM" : "ami-0da96764" },
      "us-west-2"      : { "32" : "ami-38fe7308", "64" : "ami-30fe7300", "64HVM" : "NOT_YET_SUPPORTED" },
      "us-west-1"      : { "32" : "ami-11d68a54", "64" : "ami-1bd68a5e", "64HVM" : "NOT_YET_SUPPORTED" },
      "eu-west-1"      : { "32" : "ami-973b06e3", "64" : "ami-953b06e1", "64HVM" : "NOT_YET_SUPPORTED" },
      "ap-southeast-1" : { "32" : "ami-b4b0cae6", "64" : "ami-beb0caec", "64HVM" : "NOT_YET_SUPPORTED" },
      "ap-southeast-2" : { "32" : "ami-b3990e89", "64" : "ami-bd990e87", "64HVM" : "NOT_YET_SUPPORTED" },
      "ap-northeast-1" : { "32" : "ami-0644f007", "64" : "ami-0a44f00b", "64HVM" : "NOT_YET_SUPPORTED" },
      "sa-east-1"      : { "32" : "ami-3e3be423", "64" : "ami-3c3be421", "64HVM" : "NOT_YET_SUPPORTED" }
    }
  },
    
  "Resources" : {   


    "WebServerSecurityGroup" : {
      "Type" : "AWS::EC2::SecurityGroup",
      "Properties" : {
        "GroupDescription" : "Enable SSH access and HTTP from the load balancer only",
        "SecurityGroupIngress" : [
          {"IpProtocol" : "tcp", "FromPort" : "22", "ToPort" : "22", "CidrIp" : { "Ref" : "SSHLocation"}},
          { "IpProtocol" : "tcp", "FromPort" : "80", "ToPort" : "80", "SourceSecurityGroupOwnerId" : {"Fn::GetAtt" : ["ElasticLoadBalancer", "SourceSecurityGroup.OwnerAlias"]}, "SourceSecurityGroupName" : {"Fn::GetAtt" : ["ElasticLoadBalancer", "SourceSecurityGroup.GroupName"]}}
        ]
      }
    },  

    "ElasticLoadBalancer" : {
      "Type" : "AWS::ElasticLoadBalancing::LoadBalancer",
      "Properties" : {
        "AvailabilityZones" : { "Fn::GetAZs" : "" },
        "Listeners" : [ {
          "LoadBalancerPort" : "80",
          "InstancePort" : "80",
          "Protocol" : "HTTP"
        } ],
        "HealthCheck" : {
          "Target" : "HTTP:80/",
          "HealthyThreshold" : "3",
          "UnhealthyThreshold" : "5",
          "Interval" : "30",
          "Timeout" : "5"
        }
      }
    },

    "WebServerGroup" : {
      "Type" : "AWS::AutoScaling::AutoScalingGroup",
      "Properties" : {
        "AvailabilityZones" : { "Fn::GetAZs" : ""},
        "LaunchConfigurationName" : { "Ref" : "WebServerConfig" },
        "MinSize" : "1",
        "MaxSize" : "3",
        "LoadBalancerNames" : [ { "Ref" : "ElasticLoadBalancer" } ]
      }
    },

    "WebServerConfig": {  
      "Type" : "AWS::AutoScaling::LaunchConfiguration",
      "Metadata" : {
        "Comment" : "Install a simple PHP application",
        "AWS::CloudFormation::Init" : {
          "config" : {
            "packages" : {
              "yum" : {
                "httpd"             : [],
                "php"               : []
              }
            },

            "files" : {

              "/var/www/html/index.php" : {
                "content" : { "Fn::Join" : ["", [
                  "<?php\n",
                  "echo '<h1>AWS CloudFormation sample PHP application</h1>';\n",
                  "echo 'Highly available, load balanced stack updated version via UpdateStack';\n ",
                  "?>\n"
                ]]},
                "mode"    : "000644",
                "owner"   : "apache",
                "group"   : "apache"
              },


              "/etc/cfn/cfn-hup.conf" : {
                "content" : { "Fn::Join" : ["", [
                  "[main]\n",
                  "stack=", { "Ref" : "AWS::StackId" }, "\n",
                  "region=", { "Ref" : "AWS::Region" }, "\n"
                ]]},
                "mode"    : "000400",
                "owner"   : "root",
                "group"   : "root"
              },

              "/etc/cfn/hooks.d/cfn-auto-reloader.conf" : {
                "content": { "Fn::Join" : ["", [
                  "[cfn-auto-reloader-hook]\n",
                  "triggers=post.update\n",
                  "path=Resources.WebServerConfig.Metadata.AWS::CloudFormation::Init\n",
                  "action=/opt/aws/bin/cfn-init -s ", { "Ref" : "AWS::StackId" }, " -r WebServerConfig ",
                                                   " --region     ", { "Ref" : "AWS::Region" }, "\n",
                  "runas=root\n"
                ]]}
              }
            },

            "services" : {
              "sysvinit" : {
                "httpd"    : { "enabled" : "true", "ensureRunning" : "true" },
                "sendmail" : { "enabled" : "false", "ensureRunning" : "false" }
              }
            }
          }
        }
      },

      "Properties": {
        "ImageId" : { "Fn::FindInMap" : [ "AWSRegionArch2AMI", { "Ref" : "AWS::Region" }, { "Fn::FindInMap" : [ "AWSInstanceType2Arch", { "Ref" : "WebServerInstanceType" }, "Arch" ] } ] },
        "InstanceType" : { "Ref" : "WebServerInstanceType" },
        "SecurityGroups" : [ {"Ref" : "WebServerSecurityGroup"} ],
        "KeyName" : { "Ref" : "WebServerKeyName" },
        "UserData"       : { "Fn::Base64" : { "Fn::Join" : ["", [
          "#!/bin/bash\n",
          "yum update -y aws-cfn-bootstrap\n",

          "# Helper function\n",
          "function error_exit\n",
          "{\n",
          "  /opt/aws/bin/cfn-signal -e 1 -r \"$1\" '", { "Ref" : "WebServerWaitHandle" }, "'\n",
          "  exit 1\n",
          "}\n",

          "# Install the simple web page\n",
          "/opt/aws/bin/cfn-init -s ", { "Ref" : "AWS::StackId" }, " -r WebServerConfig ",
          "         --region ", { "Ref" : "AWS::Region" }, " || error_exit 'Failed to run cfn-init'\n",

          "# Start up the cfn-hup daemon to listen for changes to the Web Server metadata\n",
          "/opt/aws/bin/cfn-hup || error_exit 'Failed to start cfn-hup'\n",

          "# All done so signal success\n",
          "/opt/aws/bin/cfn-signal -e 0 -r \"WebServer setup complete\" '", { "Ref" : "WebServerWaitHandle" }, "'\n"
        ]]}}        
      }
    },

    "WebServerWaitHandle" : {
      "Type" : "AWS::CloudFormation::WaitConditionHandle"
    },

    "WebServerWaitCondition" : {
      "Type" : "AWS::CloudFormation::WaitCondition",
      "DependsOn" : "WebServerGroup",
      "Properties" : {
        "Handle" : {"Ref" : "WebServerWaitHandle"},
        "Timeout" : "300"
      }
    }
  },
  
  "Outputs" : {
    "WebsiteURL" : {
      "Value" :  { "Fn::Join" : [ "", [ "http://", { "Fn::GetAtt" : [ "ElasticLoadBalancer", "DNSName" ]}]]},
      "Description" : "Application URL"
    }
  }
}