Termination protection is another feature of the Auto Scaling Group which allows you to protect EC2 instances from Scale-In if you feel that Scaling-In instances is not the right thing for your application. In some cases, you may want to control the scaling of instances manually, rather than trusting the Scale-In dynamically. You can enable instance protection either at the Auto Scaling Group level or on individual EC2 instances.
You can enable the instance protection at the Auto Scaling Group level using the following command:
PS C:\> Update-ASAutoScalingGroup -AutoScalingGroupName WebAppASG -NewInstancesProtectedFromscaleIn $true
To set the termination protection on an individual EC2 level, you can use the following command:
PS C:\> Edit-EC2InstanceAttribute -InstanceId i-05ba9441e9d65e0ff -DisableApiTermination $true