I have an auto-scaling group which was working fine. I made a copy of the launch configuration and changed an additional attached volume (not the root volume which is in the AMI) from Magnetic/standard to SSD/gp2. I changed the auto-scaling group to use the new launch configuration and executed a scaling policy to "Add 1 instances".
Then EC2 went into a loop starting , stopping, and terminating instances. EAch instance shows a state transition reason of "Client.InstanceInitiatedShutdown: Instance initiated shutdown". The system log of each instance is empty.
I created a copy of the copied launch configuration and changed the additional volume back to Magnetic/standard and updated the auto-scaling group, but it was still looping. I executed a scaling policy to "Remove 1 instance" to get it to stop.
What did I do wrong? The AMI is fine as I have another auto-scaling group using the same AMI. The auto-scaling group was working fine until I made this change. (I changed the instance type earlier in the day with no problems.)