Amazon ECS
User Guide for AWS Fargate (API Version 2014-11-13)

Deregistering Task Definitions

If you decide that you no longer need a task definition in Amazon ECS, you can deregister the task definition so that it no longer displays in your ListTaskDefinition API calls or in the console when you want to run a task or update a service.

When you deregister a task definition, it is immediately marked as INACTIVE. Existing tasks and services that reference an INACTIVE task definition continue to run without disruption, and 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 lifecycle of any associated tasks and services.

Use the following procedure to deregister a task definition.

To deregister a task definition

  1. Open the Amazon ECS console at

  2. From the navigation bar, choose the region that contains your task definition.

  3. In the navigation pane, choose Task Definitions.

  4. On the Task Definitions page, choose the task definition name that contains one or more revisions that you want to deregister.

  5. On the Task Definition Name page, select the box to the left of each task definition revision you want to deregister.

  6. Choose Actions, Deregister.

  7. Verify the information in the Deregister Task Definition window, and choose Deregister to finish.