[CentOS] Short or long hostname ?

Wed Apr 10 13:23:18 UTC 2019
Simon Matter <simon.matter at invoca.ch>

> Hi,
> For the last ten years or so, I've defined the short hostname in
> /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check
> this information, which eventually led me to this page:
>   *
> https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name
> Now I admit I'm even more confused than before.
> Is there some reliable piece of information on this subject for CentOS ?

IMHO for those having proper DNS in place, the hostname should be set to
the FQDN in whatever place it is supposed to be set. I quite feel there is
something wrong if the only place where the FQDN is listed is the
/etc/hosts file.

I'm not very happy with how the issue was handled in Linux and the
different distributions in the last decades. Not to mention the
inconsistency in the relevant man pages.

I found the info mentioned in the FreeBSD man pages quite helpful even if
it has to be "translated" to Linux. See the excerpt of the mentioned man
pages below. If you believe this is heresy to be posted here, please don't
read it :-)


root at freebsd:~ # man hostname
HOSTNAME(1)             FreeBSD General Commands Manual           

     hostname - set or print name of current host system

     hostname [-f] [-s | -d] [name-of-host]

     The hostname utility prints the name of the current host.  The
     can set the hostname by supplying an argument; this is usually done in
     the initialization script /etc/rc.d/hostname, normally run at boot time.
     This script uses the hostname variable in /etc/rc.conf.

root at freebsd:~ # man rc.conf
RC.CONF(5)                FreeBSD File Formats Manual              

     rc.conf - system configuration information

     The file rc.conf contains descriptive information about the local host
     hostname (str) The fully qualified domain name (FQDN) of this host on
              the network.  This should almost certainly be set to
              something meaningful, even if there is no network connection.
              If dhclient(8) is used to set the hostname via DHCP, this
              variable should be set to an empty string.  Within a jail(8)
              the hostname is generally already set and this variable may
              absent.  If this value remains unset when the system is done
              booting your console login will display the default hostname
              of "Amnesiac".