Change the Hostname on Linux with hostnamectl (Permanently)

A new VPS often comes with a hostname like vps-123456 or the name you entered at order time. Giving the server a meaningful name makes prompts, logs, monitoring and email headers clearer. On systemd distributions, hostnamectl changes it permanently in one command.

Check the current hostname

hostnamectl
hostname          # short name
hostname -f       # fully qualified domain name (FQDN), resolved through /etc/hosts or DNS

Set a new hostname

sudo hostnamectl set-hostname web1.example.com

This writes /etc/hostname and applies the change immediately, with no reboot needed. Your current shell prompt updates when you open a new session (exec bash).

Short name or FQDN?

Opinions differ, and both work. Common practice:

Set /etc/hostname to the short name (web1) or the FQDN (web1.example.com) consistently across your servers.
Make sure hostname -f returns the FQDN through /etc/hosts.

Mail servers care most. Postfix uses the FQDN in its greeting, and it should match the server’s PTR (reverse DNS) record. See email VPS and PTR records.

Hostname rules: letters, digits and hyphens; each label up to 63 characters; no underscores; not starting or ending with a hyphen.

Update /etc/hosts

After a rename, sudo may print:

sudo: unable to resolve host web1: Name or service not known

The new name isn’t in /etc/hosts. Add it:

127.0.0.1   localhost
127.0.1.1   web1.example.com web1

# or with the server's public IP
203.0.113.10 web1.example.com web1

Debian and Ubuntu traditionally use 127.0.1.1 for the hostname. Put the FQDN first, then the short name. Check with:

hostname -f       # web1.example.com
getent hosts web1

Pretty and static hostnames

hostnamectl knows three kinds:

static — the one in /etc/hostname, used at boot;
transient — the running kernel hostname, which DHCP can change;
pretty — a free-form label with spaces and capitals, like Web Server 1 (Tokyo).

sudo hostnamectl set-hostname "Web Server 1" --pretty
sudo hostnamectl set-hostname web1 --static

Cloud-init resets my hostname

Many VPS images use cloud-init, which may set the hostname from the provider’s metadata at every boot and undo your change. If the name reverts after a reboot:

grep -E 'preserve_hostname|manage_etc_hosts' /etc/cloud/cloud.cfg

Set the following in /etc/cloud/cloud.cfg, or in a file in /etc/cloud/cloud.cfg.d/:

preserve_hostname: true

If manage_etc_hosts: true is set, cloud-init also regenerates /etc/hosts from a template. Either turn it off, or edit the template (/etc/cloud/templates/hosts.debian.tmpl and similar). See cloud-init.

Without systemd

echo web1 | sudo tee /etc/hostname
sudo hostname web1              # apply now

Things to update after renaming

Prompt: open a new shell.
Mail: /etc/mailname and Postfix myhostname if you send email.
Monitoring and logs: agents may report under the old name until restarted (Netdata, Prometheus node labels, rsyslog).
Self-signed certificates and SSH host keys: they don’t include the hostname in a way that breaks, but configs that match on the name (Ansible inventories, ~/.ssh/config) may need updating.
Databases: MySQL replication or Galera configs sometimes reference hostnames.
The panel: the hostname you see in your provider’s control panel is a label and doesn’t change with hostnamectl.

DNS: make the name resolvable

For other machines to reach web1.example.com, create a DNS A record pointing to the server’s IP. The hostname on the server doesn’t create DNS entries by itself. See DNS records explained.

Quick reference

Task	Command
Show	`hostnamectl`
Set	`sudo hostnamectl set-hostname name`
FQDN check	`hostname -f`
Hosts entry	`127.0.1.1 fqdn short` in `/etc/hosts`
Stop cloud-init reverting	`preserve_hostname: true`

Linux
Configuration
Networking