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7 ways to set your hostname in Fedora, CentOS, or Red Hat Enterprise Linux

There are many ways to set a hostname. Some are more efficient than others.
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A hostname is a human-readable string that helps people refer to a computer by a familiar name, rather than by a number or unwieldy descriptors like, "the third one from the bottom of the second-to-last rack." Often, a hostname is set during the installation process, but there are times when it needs to be changed. On Linux, there are many ways to set a hostname, and this article aims to cover them all.

Before exploring the tools related to hostnames, though, you must understand the different contexts in which the term is used. There are potentially two designators of a system’s hostname: the computer’s administrator (a laptop’s owner, or a server’s root user) and the network (depending on protocols and settings). This factor can lead to confusion, because you might look at your computer’s hostname and see one value, only to find that the same computer is referred to as something different over the network.

There’s a historical reason for this situation. Long ago, before DNS, hosts on a network had to be defined locally in the file /etc/hosts. If there were 31 hosts on a network and a new one was added, then 32 hosts had to update their /etc/hosts file to reflect the correct IP address and corresponding hostname for each of their neighbors. This process didn’t scale well for bigger networked systems such as the World Wide Web (the Internet), and so DNS was invented, and the concept of hostnames largely was abstracted away from local computers to instead be managed by the network.

Today, the important hostname is the one the network uses. The hostname value in /etc/hosts is often set to localhost by default.

With this context in mind, here are all the different ways to manipulate a hostname on Linux.

Change all three names with hostnamectl

The hostnamectl command from systemd can manipulate three varieties of hostnames:

  • Transient: Received from network configuration.
  • Static: Provided by the kernel.
  • Pretty: Provided by the user.

A transient hostname can change as needed to avoid name collisions. For instance, if you name your computer penguin but there’s already another host with that name on the network, your network hostname becomes penguin-1.

Static and pretty hostnames are a little like local variables: They’re used for activities occurring on the local machine, mostly as a convenience for the user, along with applications that need to know whether they’re running locally or remotely (for example, over a forwarded X session).

When invoked without any arguments, hostnamectl returns the static and pretty names, plus some system information:

$ hostnamectl
   Static hostname: penguin
   Pretty hostname: Penguin VM
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 418d9ce8ead44bbfb6970c0d356b89bf
           Boot ID: fb3a310237ef41f88b1c62c26f19065a
    Virtualization: kvm
  Operating System: Fedora 30 (Workstation Edition)
       CPE OS Name: cpe:/o:fedoraproject:fedora:30
            Kernel: Linux 5.0.9-301.fc30.x86_64
      Architecture: x86-64
$ sudo hostnamectl set-hostname --pretty "Web dev test environment"
$ sudo hostnamectl set-hostname --static webdev-test-env
$ hostnamectl
   Static hostname: webdev-test-env
   Pretty hostname: Web dev test environment
   [...]

Change the static and pretty names in the GUI with GNOME Settings

If you want to set the static and pretty names in a desktop application, use GNOME Settings. To launch GNOME Settings, go to the Activities menu in the upper left corner of your GNOME desktop. Type Settings into the search field, or click the Show Applications icon on the left dock and find Settings in the application icons as shown below:

The (GNOME) Settings icon within Show Applications.The (GNOME) Settings Device menu.

$ hostnamectl
   Static hostname: rockhopper-computer
   Pretty hostname: rockhopper computer
   [...]

Change the static name with cockpit

Fedora, CentOS, and RHEL systems feature a web console application called Cockpit for monitoring and configuring local and remote machines. Using Cockpit, you can change the static hostname for your own machine, or any machine you administer (as long as it has Cockpit enabled).

First, install and enable Cockpit:

$ sudo dnf install cockpit
[...]
$ sudo systemctl enable --now cockpit

Logging into Cockpit.

In the web console, click the System tab in the left column. Click the entry for Host name and edit the Pretty Host Name and (static) Real Host Name:

Changing the pretty and static hostnames in Cockpit.

$ sudo echo "galapagos" > /etc/hostname 
$ hostnamectl
   Static hostname: snares
   Pretty hostname: rockhopper web console computer
   [...]

Change the static name in the hostname file

You can also set the static hostname manually by editing /etc/hostname. This file contains exactly one line by default. If you have not changed the hostname yet, then that line probably reads localhost.localdomain. If you have used hostnamectl to change the hostname already, then this file reflects that change.

Editing this file manually is not necessarily recommended, because it doesn’t update all the other hostname values the way hostnamectl does. For example:

$ sudo echo "galapagos" > /etc/hostname 
$ hostnamectl
   Static hostname: galapagos
   Pretty hostname: rockhopper computer
   Transient hostname: rockhopper-computer
   [...]

Change the static name with nmcli

Another way to change a static hostname is through the command line interface for Network Manager, nmcli:

$ sudo nmcli general hostname emperor
$ hostnamectl
   Static hostname: emperor
   Pretty hostname: rockhopper computer
   Transient hostname: rockhopper-computer
   [...]

Change the transient name with sysctl

The sysctl command allows you to configure kernel parameters while Linux is running (that is, instead of at boot time). Your computer’s transient hostname is a kernel parameter, so you can modify it with this command:

$ sudo sysctl kernel.hostname=humboldt
$ hostnamectl
   Static hostname: emperor
   Pretty hostname: rockhopper computer
   Transient hostname: humboldt
   [...]

Change the transient name with hostname

The hostname command from the util-linux package is a simple tool to query and set the transient hostname.

To query your current hostname:

$ hostname
humboldt
$ sudo hostname fjordland
$ hostnamectl
   Static hostname: emperor
   Pretty hostname: rockhopper computer
Transient hostname: fjordland

Be careful with /etc/hosts

The /etc/hosts file is mostly historic, although it is used by some applications and protocols, and can be a useful method for creating shortcuts to hosts you use often. You can use it to set a hostname, but usually, you’re just creating an alias to localhost at IP address 127.0.0.1 (your computer’s network loopback address).

For example, if you change /etc/hosts from the default entries like this:

$ cat /etc/hosts
127.0.0.1   magellanic magellanic.localdomain magellanic magellanic.localdomain4
::1         magellanic magellanic.localdomain magellanic magellanic.localdomain6
$ ping -c 1 localhost
PING localhost(magellanic (::1)) 56 data bytes
64 bytes from magellanic (::1): icmp_seq=1 ttl=64 time=0.182 ms
[...]
$ ping -c 1 magellanic
PING magellanic(magellanic (::1)) 56 data bytes
64 bytes from magellanic (::1): icmp_seq=1 ttl=64 time=0.181 ms
[...]
$ hostnamectl
   Static hostname: emperor
   Pretty hostname: rockhopper computer
   Transient hostname: fjordland

Follow the conformity convention

As you can tell from the iterations within this article, a computer’s hostname can get confusing should you use too many methods to set it, or if you change it frequently. While nothing enforces uniformity across hostname types, it’s a convention to keep everything the same on each computer.

Choose a memorable name and use it for your pretty name. Let the static and transient names be derived from that. Just as importantly, in a large network, choose meaningful names. For instance, all upper management computers may be named after a D&D monster, while all computers in the IT department may be named after a famous starship, and so on. Using a naming schema helps avoid name collisions and provides context to an otherwise dizzying list of network hosts.

Topics:   Linux  
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Seth Kenlon

Seth Kenlon is a free culture advocate and UNIX geek. More about me

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