Tricky question!

I see this asg with a TargetTrackingPolicy for both scale up (if queue size >0) and down, but scale down goes (additionally or only) through a custom policy – check if specific machine can be shutdown. For this we need to make sure there's no job running there. Two ways to do it –

1. Instance protection set on/off which is simple.
2. Compare machines that the ASG wants to shutdown with machines having tasks {} retrieved from the API. If task is running, avoid shutting down this machine. This can happen in a Lambda function.