CODEWITHSUNDEEP
amazon-web-servicesaws-cloudformationamazon-elastic-beanstalk
mico
mico

Reputation: 12748

How to build a solution of CloudFormation and Elastic Beanstalk that has only one EC2 instance?

This direct CloudFormation code snippet is part from example ElasticBeanstalk application provided in https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/sample-templates-services-ap-south-1.html 

    "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"
        }
      }
    },

I have only the Free Tier account on AWS, so I do not want to cast money to test how this behaves. Description says:

WARNING This template creates one or more Amazon EC2 instances and an Amazon Relational Database Service database instance. You will be billed for the AWS resources used if you create a stack from this template.

My issue is to know, how many instances this would create if launched? I do not see any constraints, but the Mappings part seems so long, that I suppose more than one is at least there. Conditions has two entries, does that mean two instances also? I would like to find a solution with only one instance running, would it be enough to just limit the regions or how to limit amount of EC2 created to only one?

Upvotes: 1

Views: 294

Answers (2)

mico
mico

Reputation: 12748

Actually, I found a way to go:

I took this solution as a base one:

AWSTemplateFormatVersion: '2010-09-09'
Resources:
  sampleApplication:
    Type: AWS::ElasticBeanstalk::Application
    Properties:
      Description: AWS Elastic Beanstalk Sample Application
  sampleApplicationVersion:
    Type: AWS::ElasticBeanstalk::ApplicationVersion
    Properties:
      ApplicationName:
        Ref: sampleApplication
      Description: AWS ElasticBeanstalk Sample Application Version
      SourceBundle:
        S3Bucket: !Sub "elasticbeanstalk-samples-${AWS::Region}"
        S3Key: php-newsample-app.zip
  sampleConfigurationTemplate:
    Type: AWS::ElasticBeanstalk::ConfigurationTemplate
    Properties:
      ApplicationName:
        Ref: sampleApplication
      Description: AWS ElasticBeanstalk Sample Configuration Template
      OptionSettings:
      - Namespace: aws:autoscaling:asg
        OptionName: MinSize
        Value: '2'
      - Namespace: aws:autoscaling:asg
        OptionName: MaxSize
        Value: '6'
      - Namespace: aws:elasticbeanstalk:environment
        OptionName: EnvironmentType
        Value: LoadBalanced
      SolutionStackName: 64bit Amazon Linux 2018.03 v2.8.15 running PHP 7.2
  sampleEnvironment:
    Type: AWS::ElasticBeanstalk::Environment
    Properties:
      ApplicationName:
        Ref: sampleApplication
      Description: AWS ElasticBeanstalk Sample Environment
      TemplateName:
        Ref: sampleConfigurationTemplate
      VersionLabel:
        Ref: sampleApplicationVersion

(found in https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/quickref-elasticbeanstalk.html)

There if I change EnvironmentType to SingleInstance, I get a single instance solution like I want.

(found in https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/command-options-general.html#command-options-general-elasticbeanstalkenvironment)

I haven't tested this yet, but I suppose that at the same way I can drop the MinSize and MaxSize because, this is single instance.

Upvotes: 1

JohnB
JohnB

Reputation: 958

I think your using this template. https://s3-ap-south-1.amazonaws.com/cloudformation-templates-ap-south-1/ElasticBeanstalk_Simple.template

In which case its creating a database which is a db.t2.small. Amazon Free Tier for an RDS is exclusively a db.t2.micro. If you edit the template to the free tier that warning should disappear

More info here: https://aws.amazon.com/rds/free/

Upvotes: 1

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