AWS ECS task definition cleanup

Python CLI utility to help maintain legacy AWS ECS task definitions.

The utility offers the following:

• Set task definitions ACTIVE -> INACTIVE that are not associated to ECS tasks.
• Mark currently INACTIVE task definitions for deletion by ECS.

Requirements

• Python 3.10+
• Boto3

   pip install boto3

Usage

Note: adding a --commit argument will apply changes to ECS task definitions, otherwise all commands are executed in a safe "dry run" mode.

Locate task definitions unused by ECS tasks, set INACTIVE:

AWS_REGION="ap-southeast-2" \
  ./cleanup.py --set-inactive

By default --set-inactive will not mark task definitions INACTIVE if any version of said definition is in use.

For example:

• Task definition arn:aws:ecs:REGION:ACCOUNT_ID:task-definition/my-task-definition:123 is currently in use by an ECS task.
• Utility locates unused task definition arn:aws:ecs:REGION:ACCOUNT_ID:task-definition/my-task-definition:666, but will not mark INACTIVE as there are other my-task-definition:* definition versions in use.

In order to set all unused task definition versions INACTIVE - only leaving in use definition versions ACTIVE:

AWS_REGION="ap-southeast-2" \
  ./cleanup.py --set-inactive=aggressive

Mark currently INACTIVE task definitions for deletion by the ECS subsystem:

AWS_REGION="ap-southeast-2" \
  ./cleanup.py --delete-inactive

Finally, both operations can be executed together:

AWS_REGION="ap-southeast-2" \
  ./cleanup.py --set-inactive=aggressive --delete-inactive

Reference

• https://aws.amazon.com/blogs/containers/announcing-amazon-ecs-task-definition-deletion/
• https://docs.aws.amazon.com/AmazonECS/latest/developerguide/deregister-task-definition-v2.html
• https://docs.aws.amazon.com/AmazonECS/latest/developerguide/delete-task-definition-v2.html