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

Symptoms

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

Cause

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.

Resolution

Note: The following workaround scripts may interfere with WHM's Change Hostname feature, which causes hostname configuration issues and a locked cPanel & WHM license.

1. Log in to the server via SSH or WHM's Terminal as the root user

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:

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

   Note: "$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.