Replace Auto Scaling instances based on an instance refresh

You can use an instance refresh to update the instances in your Auto Scaling group instead of manually replacing instances a few at a time. This can be useful when a configuration change requires you to replace instances, and you have a large number of instances in your Auto Scaling group.

An instance refresh can be helpful when you have a new Amazon Machine Image (AMI) or a new user data script. To use an instance refresh, first create a new launch template that specifies the new AMI or user data script. Then, start an instance refresh to begin updating the instances in the group immediately.

An instance refresh can also be helpful when you are migrating your Auto Scaling groups from launch configurations to launch templates. First, copy your launch configurations to new launch templates. Then, start an instance refresh that specifies the launch template as part of the desired configuration to begin updating the instances in the group immediately. For more information about migrating to launch templates, see Migrate to launch templates.