I've noticed that the "preferred" method of setting the system hostname is fundamentally different between Red Hat/CentOS and Debian/Ubuntu systems.
HOSTNAME=<value>, where should be the Fully Qualified Domain Name (FQDN), such as hostname.expample.com, but can be whatever hostname is necessary.
The RHEL install guide is slightly more ambiguous:
Setup prompts you to supply a host name for this computer, either as a fully-qualified domain name (FQDN) in the format hostname.domainname or as a short host name in the format hostname.
The Debian reference says the hostname should not use the FQDN:
3.5.5. The hostname
The kernel maintains the system hostname. The init script in runlevel S which is symlinked to "/etc/init.d/hostname.sh" sets the system hostname at boot time (using the hostname command) to the name stored in "/etc/hostname". This file should contain only the system hostname, not a fully qualified domain name.
I haven't seen any specific recommendations from IBM about which to use, but some software seems to have a preference.
- In a heterogeneous environment, is it better to use the vendor recommendation, or choose one and be consistent across all hosts?
- What software have you encountered which is sensitive to whether the hostname is set to the FQDN or short name?