I have a redhat (EL5) server that I need to change the hostname on. I'm trying to put it back into a known state to help with server provisioning activities.

As part of changing the hostname, I'm updating /etc/sysconfig/network and /etc/hosts. I also have an explicit call to hostname. My desired state is that the server thinks its hostname is "localhost". And a call to "hostname" returns "localhost".

The problem I'm having is that when I reboot, the hostname is reverted to "localhost.companyname.com" which is not what I want. How do I ensure that the hostname is set up as just "localhost" when I reboot?

My /etc/sysconfig/network file contains:

NETWORKING=yes
HOSTNAME=localhost
GATEWAY=123.123.123.123 #I do have a proper IP address here

My /etc/hosts file contains:

127.0.0.1       localhost.localdomain   localhost
172.21.1.1      localhost.companyname.com     localhost