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What is a launch template and how is it used by an Auto Scaling Group? What scaling policies are available in Auto Scaling Groups, such as target tracking and step scaling? How do health checks work within an Auto Scaling Group to maintain a healthy fleet of instances? How can Auto Scaling Groups span multiple Availability Zones to improve application availability? How can predictive scaling in Auto Scaling Groups improve upon reactive scaling policies?
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How do lifecycle hooks in Auto Scaling Groups let you customize instance launch and termination behavior?

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Lifecycle hooks let you pause an instance in a wait state during either the launch or termination process, giving you time to perform custom actions, such as running configuration scripts before an instance becomes fully active, or gracefully draining active connections and backing up logs before an instance is terminated, before the Auto Scaling Group is allowed to proceed with completing that lifecycle transition.
aws autoscaling put-lifecycle-hook --lifecycle-hook-name my-hook --auto-scaling-group-name my-asg --lifecycle-transition autoscaling:EC2_INSTANCE_TERMINATING --heartbeat-timeout 300
Real-world example A logging service uses a termination lifecycle hook to ensure that any pending log files on an instance are safely uploaded to S3 before that instance is fully terminated by the Auto Scaling Group, preventing any log data loss.

Common follow-ups: What happens if a lifecycle hook's custom action never completes?;How do lifecycle hooks integrate with Lambda or SNS notifications?

AWS Backup & Disaster Recovery;Lambda & Serverless
All 7 Auto Scaling Groups questions