First of all, what I’m trying to achieve is scale-out/scale-in during deployment with aws update-service so that instance would not require double the memory of service (which is quite demanding memory-wise) at all times.

I have set a target tracking in AWS application autoscaling with min 3 instances and max 32. The target value is set to 80 of CPU utilization. Once we reach the target value for 3 minutes, the cloudwatch triggers scale out. However, the newly created instances of our service are not warmed up well, so it distrupts the average of CPU usage with more spikes, so the target tracking scales out even more, creating even more spikes and so on. The cooldown doesn’t seem to help here as the scaling will occur anyway if the spikes become bigger than previous spikes.