Considerations for suspending processes

Suspending AlarmNotification allows you to temporarily stop the group's target tracking, step, and simple scaling policies without deleting the scaling policies or their associated CloudWatch alarms. To temporarily stop individual scaling policies instead, see Disable a scaling policy for an Auto Scaling group.

You might choose to suspend the HealthCheck and ReplaceUnhealthy processes to reboot instances without Amazon EC2 Auto Scaling terminating the instances based on its health checks. However, if you need Amazon EC2 Auto Scaling to continue performing health checks on the remaining instances, use the standby feature instead. For more information, see Temporarily remove instances from your Auto Scaling group.

If you suspend the Launch and Terminate processes, or AZRebalance, and then you make changes to your Auto Scaling group, for example, by detaching instances or changing the Availability Zones that are specified, your group can become unbalanced between Availability Zones. If that happens, after you resume the suspended processes, Amazon EC2 Auto Scaling gradually redistributes instances evenly between the Availability Zones.

If you suspend the Terminate process, you can still force instances to be terminated by using the delete-auto-scaling-group command with the force delete option.

Suspending the Terminate process applies only to instances that are currently in the InService state. It does not prevent the termination of instances in other states, such as Pending, or instances that fail to resume properly from standby.

The RemoveFromLoadBalancerLowPriority process can be ignored when it is present in calls to describe Auto Scaling groups using the AWS CLI or SDKs. This process is deprecated and is retained only for backward compatibility.