Updating rather than replacing ECS Task Definition with CloudFormation

Question

When updating a TaskDefinition in CloudFormation the docs say that a replacement action occurs - http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ecs-taskdefinition.html

Is there a way to get that to be a new revision? Should I be using the family parameter? Is there a TaskDefinition limit? Otherwise I end up with a large number of inactive definitions.

ContainerDefinitions:
  - Name: container
    Essential: 'true'
    Image: image:tag
    PortMappings:
      - ContainerPort: 80
        HostPort: 80
        Protocol: 'tcp'
    TaskRoleArn: 'arn:aws:iam::role'

Answer 1

Yes, in order to put your changes in a new revision of the same Task Definition you should use the Family parameter. Quoting from the official documentation :

Family

The name of a family that this task definition is registered to. A family groups multiple versions of a task definition.

CloudFormation will still consider this a "replacement" and will delete the old revision, however it will not create a new Task Definition if you use the Family parameter.

Answer 2

Actually, parameter Family , as decribed above is not working, even you inform it, Task Definition are replaced, but I saw in other thread that you can do it using following sintaxe in your template:

...
"Type": "AWS::ECS::TaskDefinition", 
"UpdateReplacePolicy": "Retain", 
"Properties": {
....