During the last exercise, you made use of the EC2 Metadata service to get the Instance ID of the EC2 instance, which exists on every instance at http://169.254.169.254, a non-routable IP address. Instance metadata is useful if you want to develop automation that configures an instance dynamically when it launches. For example, you may want to add a Linux server to a cluster of some kind whenever it launches. You can use the instance metadata to retrieve the IP address of the system and add it to a cluster at boot time.