Mounting EFS to AWS Fargate using Terraform - PlatformTaskDefinitionIncompatibilityException error:

You simply require to upgrade your ecs service to latest version

resource "aws_ecs_service" "service" {
  platform_version = "1.4.0"
  launch_type      = "FARGATE"
  ...
}

efs feature is only available on the latest version

When you don’t specify platform_version, it will default to LATEST which is set to 1.3.0 which doesn’t allow efs volumes.

UPDATE: As of 1/21/22, it seems that the LATEST ECS service version is 1.4.0, so explicitly specifying the ECS platform version is no longer necessary to have EFS mounts work. Per:

https://docs.aws.amazon.com/AmazonECS/latest/developerguide/platform-linux-fargate.html