aws_lb_ha.template

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

  "Description" : "AWS CloudFormation Sample Template",

  "Parameters" : {

    "KeyName" : {
      "Description" : "Name of an existing EC2 KeyPair to enable SSH access to the instances",
      "Type" : "String",
      "Default" : "lxiaojun"
    },

    "InstanceType" : {
      "Description" : "WebServer EC2 instance type",
      "Type" : "String",
      "Default" : "m1.small",
      "AllowedValues" : [ "m1.tiny", "m1.small", "m1.medium", "m1.large", "m1.xlarge" ],
      "ConstraintDescription" : "must be a valid EC2 instance type."
    },

    "SubnetId" : {
      "Type" : "String",
      "Default" : "5f496f20-9d74-44b3-87f8-fee38c99ca87"
    },

    "LinuxDistribution": {
      "Default": "Fedora-x86_64-20-20131211.1-sda",
      "Description" : "Distribution of choice",
      "Type": "String"
    }
  },

  "Resources" : {
    "CfnUser" : {
      "Type" : "AWS::IAM::User"
    },
    "WebServerKeys" : {
      "Type" : "AWS::IAM::AccessKey",
      "Properties" : {
        "UserName" : {"Ref": "CfnUser"}
      }
    },
    "WebServerGroup" : {
      "Type" : "AWS::AutoScaling::AutoScalingGroup",
      "Properties" : {
        "AvailabilityZones" : { "Fn::GetAZs" : ""},
        "LaunchConfigurationName" : { "Ref" : "LaunchConfig" },
        "MinSize" : "1",
        "MaxSize" : "3",
        "LoadBalancerNames" : [ { "Ref" : "ELB" } ],
        "VPCZoneIdentifier" : [ { "Ref" : "SubnetId"} ]
      }
    },

    "WebServerScaleUpPolicy" : {
      "Type" : "AWS::AutoScaling::ScalingPolicy",
      "Properties" : {
        "AdjustmentType" : "ChangeInCapacity",
        "AutoScalingGroupName" : { "Ref" : "WebServerGroup" },
        "Cooldown" : "60",
        "ScalingAdjustment" : "1"
      }
    },

    "WebServerScaleDownPolicy" : {
      "Type" : "AWS::AutoScaling::ScalingPolicy",
      "Properties" : {
        "AdjustmentType" : "ChangeInCapacity",
        "AutoScalingGroupName" : { "Ref" : "WebServerGroup" },
        "Cooldown" : "60",
        "ScalingAdjustment" : "-1"
      }
    },

    "MEMAlarmHigh": {
     "Type": "AWS::CloudWatch::Alarm",
     "Properties": {
        "AlarmDescription": "Scale-up if MEM > 50% for 1 minute",
        "MetricName": "MemoryUtilization",
        "Namespace": "system/linux",
        "Statistic": "Average",
        "Period": "60",
        "EvaluationPeriods": "1",
        "Threshold": "50",
        "AlarmActions": [ { "Ref": "WebServerScaleUpPolicy" } ],
        "Dimensions": [
          {
            "Name": "AutoScalingGroupName",
            "Value": { "Ref": "WebServerGroup" }
          }
        ],
        "ComparisonOperator": "GreaterThanThreshold"
      }
    },
    "MEMAlarmLow": {
     "Type": "AWS::CloudWatch::Alarm",
     "Properties": {
        "AlarmDescription": "Scale-down if MEM < 15% for 1 minute",
        "MetricName": "MemoryUtilization",
        "Namespace": "system/linux",
        "Statistic": "Average",
        "Period": "60",
        "EvaluationPeriods": "1",
        "Threshold": "15",
        "AlarmActions": [ { "Ref": "WebServerScaleDownPolicy" } ],
        "Dimensions": [
          {
            "Name": "AutoScalingGroupName",
            "Value": { "Ref": "WebServerGroup" }
          }
        ],
        "ComparisonOperator": "LessThanThreshold"
      }
    },

    "ELB": {
      "Type": "OS::Neutron::LoadBalancer",
      "Properties": {
        "protocol_port": "80",
        "pool_id": { "Ref": "LBPool" }
      }
    },
    "LBPool": {
      "Type": "OS::Neutron::Pool",
      "Properties": {
        "lb_method": "ROUND_ROBIN",
        "protocol": "HTTP",
        "description": "Test Pool",
        "subnet_id": { "Ref" : "SubnetId"},
        "vip": {
          "protocol_port": "80",
          "connection_limit": 1000,
          "description": "Test",
          "name": "VIP"
        },
        "monitors": [{ "Ref" : "LBMonitor"}],
        "name": "LBPool"
      }
    },
    "LBMonitor": {
      "Type": "OS::Neutron::HealthMonitor",
      "Properties": {
        "delay": 3,
        "max_retries": 5,
        "url_path": "/",
        "type": "HTTP",
        "timeout": 10
      }
    },

    "LaunchConfig" : {
      "Type" : "AWS::AutoScaling::LaunchConfiguration",
      "Metadata" : {
        "AWS::CloudFormation::Init" : {
          "config" : {
            "files" : {
              "/etc/cfn/cfn-credentials" : {
                "content" : { "Fn::Join" : ["", [
                  "AWSAccessKeyId=", { "Ref" : "WebServerKeys" }, "\n",
                  "AWSSecretKey=", {"Fn::GetAtt": ["WebServerKeys",
                                    "SecretAccessKey"]}, "\n"
                ]]},
                "mode"    : "000400",
                "owner"   : "root",
                "group"   : "root"
              },
              "/etc/cfn/cfn-hup.conf" : {
                "content" : { "Fn::Join" : ["", [
                  "[main]\n",
                  "stack=", { "Ref" : "AWS::StackName" }, "\n",
                  "credential-file=/etc/cfn/cfn-credentials\n",
                  "region=", { "Ref" : "AWS::Region" }, "\n",
                  "interval=1\n"
                ]]},
                "mode"    : "000400",
                "owner"   : "root",
                "group"   : "root"
              },
              "/tmp/stats-crontab.txt" : {
                "content" : { "Fn::Join" : ["", [
                "MAIL=\"\"\n",
                "\n",
                "* * * * * /opt/aws/bin/cfn-push-stats --watch ",
                { "Ref" : "MEMAlarmHigh" }, " --mem-util\n",
                "* * * * * /opt/aws/bin/cfn-push-stats --watch ",
                { "Ref" : "MEMAlarmLow" }, " --mem-util\n"
                ]]},
                "mode"    : "000600",
                "owner"   : "root",
                "group"   : "root"
              }
            },
            "packages" : {
              "yum" : {
                "httpd"        : []
              }
            },
            "services" : {
              "systemd" : {
                "httpd"    : { "enabled" : "true", "ensureRunning" : "true" }
              }
            }
          }
        }
      },
      "Properties": {
        "ImageId" : { "Ref" : "LinuxDistribution" },
        "InstanceType"   : { "Ref" : "InstanceType" },
        "KeyName"        : { "Ref" : "KeyName" },
        "UserData"       : { "Fn::Base64" : { "Fn::Join" : ["", [
          "#!/bin/bash -v\n",
          "/opt/aws/bin/cfn-init -s ", { "Ref" : "AWS::StackName" },
          " -r LaunchConfig ",
          " --region ", { "Ref" : "AWS::Region" }, "\n",
          "echo $HOSTNAME > /var/www/html/index.html\n",
          "# install crontab\n",
          "crontab /tmp/stats-crontab.txt\n"
        ]]}}
      }
    }
  },

  "Outputs" : {
    "URL" : {
      "Description" : "The URL of the website"
    }
  }
}