Hostname resets on restart on Google Cloud Platform (CentOS 7/8)

Symptoms

On Google Cloud Platform, the system hostname is changed either on boot or after some time. This can cause license errors.

Description 

The dhclient script may not preserve the locally configured hostname, so hosting providers use scripts to work around this issue. For example, Google Cloud Platform Services™ uses the google_set_hostname script.

Workaround

Please note that the following workaround scripts may interfere with WHM's "Change Hostname" feature, which causes hostname configuration issues and a locked cPanel & WHM license.

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Create the /etc/dhcp/dhclient-exit-hooks.d directory.

   mkdir -p /etc/dhcp/dhclient-exit-hooks.d/

3. Create the zzz-set-hostname.sh file.

   touch /etc/dhcp/dhclient-exit-hooks.d/zzz-set-hostname.sh

4. Open zzz-set-hostname.sh in your preferred text editor.
5. Add the following information.

   #!/bin/sh
   hostname $host.domain.tld 
   /scripts/fixetchosts

   Please note that "$host.domain.tld" must be replaced with the server's hostname.
6. Save the changes and exit the text editor.
7. Set the executable permission on zzz-set-hostname.sh.

   chmod +x /etc/dhcp/dhclient-exit-hooks.d/zzz-set-hostname.sh

8. Reboot the server.