Amazon EC2 Container Service
API Reference (API Version 2014-11-13)


Deregisters the specified task definition by family and revision. Upon deregistration, the task definition is marked as INACTIVE. Existing tasks and services that reference an INACTIVE task definition continue to run without disruption. Existing services that reference an INACTIVE task definition can still scale up or down by modifying the service's desired count.

You cannot use an INACTIVE task definition to run new tasks or create new services, and you cannot update an existing service to reference an INACTIVE task definition (although there may be up to a 10 minute window following deregistration where these restrictions have not yet taken effect).


At this time, INACTIVE task definitions remain discoverable in your account indefinitely; however, this behavior is subject to change in the future, so you should not rely on INACTIVE task definitions persisting beyond the life cycle of any associated tasks and services.

Request Syntax

{ "taskDefinition": "string" }

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.


The family and revision (family:revision) or full Amazon Resource Name (ARN) of the task definition to deregister. You must specify a revision.

Type: String

Required: Yes

Response Syntax

{ "taskDefinition": { "containerDefinitions": [ { "command": [ "string" ], "cpu": number, "disableNetworking": boolean, "dnsSearchDomains": [ "string" ], "dnsServers": [ "string" ], "dockerLabels": { "string" : "string" }, "dockerSecurityOptions": [ "string" ], "entryPoint": [ "string" ], "environment": [ { "name": "string", "value": "string" } ], "essential": boolean, "extraHosts": [ { "hostname": "string", "ipAddress": "string" } ], "hostname": "string", "image": "string", "links": [ "string" ], "logConfiguration": { "logDriver": "string", "options": { "string" : "string" } }, "memory": number, "memoryReservation": number, "mountPoints": [ { "containerPath": "string", "readOnly": boolean, "sourceVolume": "string" } ], "name": "string", "portMappings": [ { "containerPort": number, "hostPort": number, "protocol": "string" } ], "privileged": boolean, "readonlyRootFilesystem": boolean, "ulimits": [ { "hardLimit": number, "name": "string", "softLimit": number } ], "user": "string", "volumesFrom": [ { "readOnly": boolean, "sourceContainer": "string" } ], "workingDirectory": "string" } ], "family": "string", "networkMode": "string", "placementConstraints": [ { "expression": "string", "type": "string" } ], "requiresAttributes": [ { "name": "string", "targetId": "string", "targetType": "string", "value": "string" } ], "revision": number, "status": "string", "taskDefinitionArn": "string", "taskRoleArn": "string", "volumes": [ { "host": { "sourcePath": "string" }, "name": "string" } ] } }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.


The full description of the deregistered task.

Type: TaskDefinition object


For information about the errors that are common to all actions, see Common Errors.


These errors are usually caused by a client action, such as using an action or resource on behalf of a user that doesn't have permission to use the action or resource, or specifying an identifier that is not valid.

HTTP Status Code: 400


The specified parameter is invalid. Review the available parameters for the API request.

HTTP Status Code: 400


These errors are usually caused by a server issue.

HTTP Status Code: 500


In the following example or examples, the Authorization header contents (AUTHPARAMS) must be replaced with an AWS Signature Version 4 signature. For more information about creating these signatures, see Signature Version 4 Signing Process in the AWS General Reference.

You only need to learn how to sign HTTP requests if you intend to manually create them. When you use the AWS Command Line Interface (AWS CLI) or one of the AWS SDKs to make requests to AWS, these tools automatically sign the requests for you with the access key that you specify when you configure the tools. When you use these tools, you don't need to learn how to sign requests yourself.


The following example request deregisters the first revision of the cpu-wave task definition family (cpu-wave:1). Note that in the resulting output, the task definition status becomes INACTIVE.

Sample Request

POST / HTTP/1.1 Host: Accept-Encoding: identity Content-Length: 35 X-Amz-Target: AmazonEC2ContainerServiceV20141113.DeregisterTaskDefinition X-Amz-Date: 20150429T184806Z Content-Type: application/x-amz-json-1.1 Authorization: AUTHPARAMS { "taskDefinition": "cpu-wave:1" }

Sample Response

HTTP/1.1 200 OK Server: Server Date: Fri, 12 Jun 2015 23:07:39 GMT Content-Type: application/x-amz-json-1.1 Content-Length: 491 Connection: keep-alive x-amzn-RequestId: 123a4b56-7c89-01d2-3ef4-example5678f { "taskDefinition": { "containerDefinitions": [ { "command": [ "apt-get update; apt-get install stress; while true; do stress --cpu $(( RANDOM % 4 )) -t $(( RANDOM % 10 )); done" ], "cpu": 50, "entryPoint": [ "bash", "-c" ], "environment": [], "essential": true, "image": "ubuntu", "memory": 100, "mountPoints": [], "name": "wave", "portMappings": [], "volumesFrom": [] } ], "family": "cpu-wave", "revision": 1, "status": "INACTIVE", "taskDefinitionArn": "arn:aws:ecs:us-west-2:012345678910:task-definition/cpu-wave:1", "volumes": [] } }

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: