如何构建仅具有一个EC2实例的CloudFormation和Elastic Beanstalk解决方案？

Question

此直接CloudFormation代码段来自https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/sample-templates-services-ap-south-1.html中提供的示例ElasticBeanstalk应用程序的一部分

    "Mappings" : {
    "Region2Principal" : {
      "us-east-1"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "us-west-2"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "us-west-1"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "eu-west-1"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "eu-west-2"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "eu-west-3"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-southeast-1" : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-northeast-1" : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-northeast-2" : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-northeast-3" : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-southeast-2" : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ap-south-1"     : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "us-east-2"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "ca-central-1"   : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "sa-east-1"      : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "cn-north-1"     : { "EC2Principal" : "ec2.amazonaws.com.cn", "OpsWorksPrincipal" : "opsworks.amazonaws.com.cn" },
      "cn-northwest-1" : { "EC2Principal" : "ec2.amazonaws.com.cn", "OpsWorksPrincipal" : "opsworks.amazonaws.com.cn" },
      "eu-central-1"   : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" },
      "eu-north-1"     : { "EC2Principal" : "ec2.amazonaws.com", "OpsWorksPrincipal" : "opsworks.amazonaws.com" }
    }

  },

  "Conditions" : {
    "Is-EC2-VPC"     : { "Fn::Or" : [ {"Fn::Equals" : [{"Ref" : "AWS::Region"}, "eu-central-1" ]},
                                      {"Fn::Equals" : [{"Ref" : "AWS::Region"}, "cn-north-1" ]}]},
    "Is-EC2-Classic" : { "Fn::Not" : [{ "Condition" : "Is-EC2-VPC"}]}
  },

  "Resources": {
    "WebServerRole": {
      "Type": "AWS::IAM::Role",
      "Properties" : {
        "AssumeRolePolicyDocument" : {
          "Statement"  : [{
            "Effect"   : "Allow",
            "Principal": { "Service": [{ "Fn::FindInMap" : ["Region2Principal", {"Ref" : "AWS::Region"}, "EC2Principal"]}] },
            "Action"   : [ "sts:AssumeRole" ]
          } ]
        },
        "Path": "/"
      }
    },

    "WebServerRolePolicy": {
      "Type": "AWS::IAM::Policy",
      "Properties": {
        "PolicyName" : "WebServerRole",
        "PolicyDocument" : {
          "Statement"  : [ {
            "Effect"    : "Allow",
            "NotAction" : "iam:*",
            "Resource"  : "*"
          } ]
        },
        "Roles": [ { "Ref": "WebServerRole" } ]
      }
    },

    "WebServerInstanceProfile": {
      "Type": "AWS::IAM::InstanceProfile",
      "Properties": {
        "Path": "/",
        "Roles": [ { "Ref": "WebServerRole" } ]
      }
    },

    "SampleApplication": {
      "Type": "AWS::ElasticBeanstalk::Application",
      "Properties": {
        "Description": "AWS Elastic Beanstalk Sample Application"
      }
    },

    "SampleApplicationVersion" : {
      "Type" : "AWS::ElasticBeanstalk::ApplicationVersion",
      "Properties" : {
        "Description" : "Version 1.0",
        "ApplicationName" : { "Ref" : "SampleApplication" },
        "SourceBundle" : {
          "S3Bucket": { "Fn::Join" : ["-", ["cloudformation-examples", {"Ref" : "AWS::Region" }]]},
          "S3Key": "CloudFormationBeanstalkRDSExample.war"
        }
      }
    },

我在AWS上只有免费套餐帐户，因此我不想投入金钱来测试其行为。说明说：

WARNING此模板创建一个或多个Amazon EC2实例和一个Amazon Relational Database Service数据库实例。如果从此模板创建堆栈，则将向您收取所用AWS资源的费用。

我的问题是知道，如果启动将创建多少个实例？我没有看到任何约束，但是Mappings部分似乎很长，以至于我认为至少有一个以上的约束。 Conditions有两个条目，是否也意味着两个实例？我想找到一个仅运行一个实例的解决方案，仅限制区域还是如何将创建的EC2数量限制为仅一个？

Answer 1

我认为您正在使用此模板。 https://s3-ap-south-1.amazonaws.com/cloudformation-templates-ap-south-1/ElasticBeanstalk_Simple.template

在这种情况下，它创建的数据库是db.t2.small。用于RDS的Amazon Free Tier仅是db.t2.micro。如果将模板编辑为免费层，则警告应消失