This is the new Amazon CloudFormation Template Reference Guide. Please update your bookmarks and links. For help getting started with CloudFormation, see the Amazon CloudFormation User Guide.
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 Amazon CloudFormation User Guide.
Note
If a resource with a condition isn't created, any resources that depend on that resource aren't created either, regardless of their own conditions.
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.
JSON
{ "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"}]]} } } } }
YAML
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.
JSON
{ "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"}]]} } } } }
YAML
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 Amazon Web Services 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 Amazon values
using pseudo parameters in the Amazon CloudFormation User Guide.
JSON
{ "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"}]]} } } } }
YAML
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}