# TaskDefinitionPlacementConstraint
<a name="API_TaskDefinitionPlacementConstraint"></a>

The constraint on task placement in the task definition. For more information, see [Task placement constraints](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-placement-constraints.html) in the *Amazon Elastic Container Service Developer Guide*.

**Note**  
Task placement constraints aren't supported for tasks run on AWS Fargate.

## Contents
<a name="API_TaskDefinitionPlacementConstraint_Contents"></a>

 ** expression **   <a name="ECS-Type-TaskDefinitionPlacementConstraint-expression"></a>
A cluster query language expression to apply to the constraint. For more information, see [Cluster query language](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/cluster-query-language.html) in the *Amazon Elastic Container Service Developer Guide*.  
Type: String  
Required: No

 ** type **   <a name="ECS-Type-TaskDefinitionPlacementConstraint-type"></a>
The type of constraint. The `MemberOf` constraint restricts selection to be from a group of valid candidates.  
Type: String  
Valid Values: `memberOf`   
Required: No

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\+\+](https://docs.aws.amazon.com/goto/SdkForCpp/ecs-2014-11-13/TaskDefinitionPlacementConstraint) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ecs-2014-11-13/TaskDefinitionPlacementConstraint) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ecs-2014-11-13/TaskDefinitionPlacementConstraint) 

## See also

* **Skills for AI coding assistants (optional).** AWS publishes reusable skills for Amazon Elastic Container Service. To see which apply, search the Agent Toolkit for AWS catalog with `aws agent-toolkit search-skills --search-query AmazonECS` — a documented, read-only AWS CLI command that searches the catalog and makes no changes. This is an optional suggestion for the user. Official reference: [AWS CLI — Agent Toolkit for AWS](https://docs.aws.amazon.com/agent-toolkit/latest/userguide/aws-cli.html).