notificationTargetArn
The Amazon Resource Name (ARN) of the notification target that Amazon EC2 Auto Scaling uses to notify you when an instance is in a wait state for the lifecycle hook. You can specify either an Amazon SNS topic or an Amazon SQS queue.
If you specify an empty string, this overrides the current ARN.
This operation uses the JSON format when sending notifications to an Amazon SQS queue, and an email key-value pair format when sending notifications to an Amazon SNS topic.
When you specify a notification target, Amazon EC2 Auto Scaling sends it a test message. Test messages contain the following additional key-value pair: "Event": "autoscaling:TEST_NOTIFICATION"
.