Condition attribute

To create resources in CloudFormation based on conditions, first declare your condition in the template's Conditions section. Then, use the Condition key along with the condition's logical ID as an attribute on the resource. CloudFormation creates the resource only when the condition evaluates to true. This lets you control resource creation based on specific criteria or parameters you define in your template.

If you're new to using conditions in your templates, we recommend you first review the CloudFormation template Conditions syntax topic in the AWS CloudFormation User Guide.

Example

The following template contains an Amazon S3 bucket resource with a Condition attribute. The bucket is only created if the CreateBucket condition evaluates to true.

{
   "AWSTemplateFormatVersion" : "2010-09-09",
   "Parameters" : {
      "EnvType" : {
         "Type" : "String",
         "AllowedValues" : ["prod", "dev"],
         "Default" : "dev",
         "Description" : "Environment type"
      }
   },
   "Conditions" : {
      "CreateBucket" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "prod"]}
   },
   "Resources" : {
      "MyBucket" : {
         "Type" : "AWS::S3::Bucket",
         "Condition" : "CreateBucket",
         "Properties" : {
            "BucketName" : {"Fn::Join" : ["-", ["mybucket", {"Ref" : "EnvType"}]]}
         }
      }
   }
}

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  EnvType:
    Type: String
    AllowedValues:
      - prod
      - dev
    Default: dev
    Description: Environment type
Conditions:
  CreateBucket: !Equals [!Ref EnvType, prod]
Resources:
  MyBucket:
    Type: AWS::S3::Bucket
    Condition: CreateBucket
    Properties:
      BucketName: !Sub mybucket-${EnvType}

Using multiple conditions

You can combine multiple conditions using intrinsic functions like Fn::And, Fn::Or, and Fn::Not to create more complex conditional logic.

{
   "AWSTemplateFormatVersion" : "2010-09-09",
   "Parameters" : {
      "EnvType" : {
         "Type" : "String",
         "AllowedValues" : ["prod", "test", "dev"],
         "Default" : "dev",
         "Description" : "Environment type"
      },
      "CreateResources" : {
         "Type" : "String",
         "AllowedValues" : ["true", "false"],
         "Default" : "true",
         "Description" : "Create resources flag"
      }
   },
   "Conditions" : {
      "IsProd" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "prod"]},
      "IsTest" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "test"]},
      "CreateResourcesFlag" : {"Fn::Equals" : [{"Ref" : "CreateResources"}, "true"]},
      "CreateProdResources" : {"Fn::And" : [{"Condition" : "IsProd"}, {"Condition" : "CreateResourcesFlag"}]},
      "CreateTestOrDevResources" : {"Fn::And" : [{"Fn::Or" : [{"Condition" : "IsTest"}, {"Fn::Not" : [{"Condition" : "IsProd"}]}]}, {"Condition" : "CreateResourcesFlag"}]}
   },
   "Resources" : {
      "ProdBucket" : {
         "Type" : "AWS::S3::Bucket",
         "Condition" : "CreateProdResources",
         "Properties" : {
            "BucketName" : {"Fn::Join" : ["-", ["prod-bucket", {"Ref" : "AWS::StackName"}]]}
         }
      },
      "TestDevBucket" : {
         "Type" : "AWS::S3::Bucket",
         "Condition" : "CreateTestOrDevResources",
         "Properties" : {
            "BucketName" : {"Fn::Join" : ["-", [{"Ref" : "EnvType"}, "bucket", {"Ref" : "AWS::StackName"}]]}
         }
      }
   }
}

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  EnvType:
    Type: String
    AllowedValues:
      - prod
      - test
      - dev
    Default: dev
    Description: Environment type
  CreateResources:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
    Default: 'true'
    Description: Create resources flag
Conditions:
  IsProd: !Equals [!Ref EnvType, prod]
  IsTest: !Equals [!Ref EnvType, test]
  CreateResourcesFlag: !Equals [!Ref CreateResources, 'true']
  CreateProdResources: !And
    - !Condition IsProd
    - !Condition CreateResourcesFlag
  CreateTestOrDevResources: !And
    - !Or
      - !Condition IsTest
      - !Not [!Condition IsProd]
    - !Condition CreateResourcesFlag
Resources:
  ProdBucket:
    Type: AWS::S3::Bucket
    Condition: CreateProdResources
    Properties:
      BucketName: !Sub prod-bucket-${AWS::StackName}
  TestDevBucket:
    Type: AWS::S3::Bucket
    Condition: CreateTestOrDevResources
    Properties:
      BucketName: !Sub ${EnvType}-bucket-${AWS::StackName}

Using AWS::AccountId in conditions

You can use pseudo parameters like AWS::AccountId in your conditions to create resources based on the AWS account where the stack is being deployed. This is useful for multi-account deployments or when you need to exclude specific accounts from receiving certain resources. For more information about pseudo parameters, see Get AWS values using pseudo parameters in the AWS CloudFormation User Guide.

{
   "AWSTemplateFormatVersion" : "2010-09-09",
   "Conditions" : {
      "ExcludeAccount1" : {"Fn::Not" : [{"Fn::Equals" : [{"Ref" : "AWS::AccountId"}, "111111111111"]}]},
      "ExcludeAccount2" : {"Fn::Not" : [{"Fn::Equals" : [{"Ref" : "AWS::AccountId"}, "222222222222"]}]},
      "ExcludeBothAccounts" : {"Fn::And" : [{"Condition" : "ExcludeAccount1"}, {"Condition" : "ExcludeAccount2"}]}
   },
   "Resources" : {
      "StandardBucket" : {
         "Type" : "AWS::S3::Bucket",
         "Properties" : {
            "BucketName" : {"Fn::Join" : ["-", ["standard-bucket", {"Ref" : "AWS::StackName"}]]}
         }
      },
      "RestrictedResource" : {
         "Type" : "AWS::SNS::Topic",
         "Condition" : "ExcludeBothAccounts",
         "Properties" : {
            "TopicName" : {"Fn::Join" : ["-", ["restricted-topic", {"Ref" : "AWS::StackName"}]]}
         }
      }
   }
}

AWSTemplateFormatVersion: 2010-09-09
Conditions:
  ExcludeAccount1: !Not [!Equals [!Ref 'AWS::AccountId', '111111111111']]
  ExcludeAccount2: !Not [!Equals [!Ref 'AWS::AccountId', '222222222222']]
  ExcludeBothAccounts: !And
    - !Condition ExcludeAccount1
    - !Condition ExcludeAccount2
Resources:
  StandardBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Sub standard-bucket-${AWS::StackName}
  RestrictedResource:
    Type: AWS::SNS::Topic
    Condition: ExcludeBothAccounts
    Properties:
      TopicName: !Sub restricted-topic-${AWS::StackName}