Can an AWS Fargate Service have 0 tasks running?

Question

I currently have a Fargate cluster that contains a service. This service always has 1 task running and is polling from SQS. The service will scale the number of tasks if SQS grows/shrinks. However, the task has a lot of idle time, where there are no messages in the queue. To save on costs, is it possible to make the service go down to 0 task?

I have been trying to do this and the service will always try to start at least 1 task.

If this is not possible, then would it be best practice for me to not use a service and have a CloudWatch alarm on SQS and just create a task directly in the cluster when the size is greater than 0, and then shut down the task when the SQS is back to 0? Essentially mimicking the functionality of a service.

Answer 1

Yes you can. You can also use a Target Tracking Policy that allow you to scale more efficiently than a Step Scaling Policy .

See https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-using-sqs-queue.html for more details (it's about EC2 but works for ECS as well).