Before a new scaled instance is InService, there might be some steps beforewards or afterwards
You can put an instance that is in the InService state into the Standby state, update some software or troubleshoot the instance, and then return the instance to service
Lifecycle hooks enable you to perform custom actions by pausing instances as an Auto Scaling group launches or terminates them
When an instance is paused, it remains in a wait state either until you complete the lifecycle action using the complete-lifecycle-action command or the CompleteLifecycleAction operation
For example, you could install or configure software on newly launched instances, or download log files from an instance before it terminates.
