On AWS EC2 instances, the hostname is typically configured automatically based on the private IPv4 address of the instance. Customers may need to set a custom hostname and ensure it persists during instance recycle or replacement. This article provides steps to configure a custom hostname and maintain it across reboots.

1. Edit the host files to set a permanent hostname:

   sudo gedit /etc/hostname /etc/hosts

2. Obtain the instance IP using instance metadata:

   curl -s http://169.254.169.254/latest/meta-data/local-ipv4

3. After configuring the desired hostname, update the user data script to include these commands. This ensures the configuration executes during each boot and persists across replacements.

4. When IP persistence is enabled, the custom hostname is often maintained during replacements because the hostname is linked to the persistent IP. If IP persistence is not configured, the hostname will not be maintained automatically.

5. For additional details on setting a static hostname in Linux (RHEL 7, CentOS 7), refer to the official AWS documentation:
   AWS Knowledge Center: Configure static hostname.

Outcome

The hostname remains consistent during instance recycle or replacement on AWS stateful nodes.