How to change hostname in Linux

Changing the hostname gives a Linux machine a stable identity in shell prompts, logs, inventory, monitoring, and remote-management tools. Renaming a fresh install that still uses a generic name such as host is a common cleanup task after provisioning a new VM, cloud instance, or physical server.

On current systemd-based systems such as Ubuntu Server 24.04, hostnamectl talks to systemd-hostnamed to manage the host name. Updating the hostname this way changes the running system immediately and writes the persistent static value to /etc/hostname, which takes precedence over transient names learned from DHCP or other network configuration.

The examples here target a current Ubuntu server. Use a lowercase DNS label such as web-01 unless your environment requires a fully qualified domain name. On Ubuntu-style installs, check /etc/hosts afterward because the old short name may still be mapped on 127.0.1.1, and treat a hostname that changes back later as a sign that cloud-init or configuration management still owns the system identity.

Steps to change hostname in Linux with hostnamectl:

Review the current hostname state and confirm that hostnamectl is available on the host.
```
$ hostnamectl status
 Static hostname: host
       Icon name: computer-vm
         Chassis: vm
Operating System: Ubuntu 24.04.3 LTS
          Kernel: Linux 6.8.0-90-generic
```
If hostnamectl is missing or the system bus is unavailable, this machine uses a different hostname-management path and these steps do not apply unchanged.
Set the new hostname with hostnamectl.
```
$ sudo hostnamectl hostname web-01
```
Use a single lowercase DNS label such as web-01 unless the environment standard requires a fully qualified domain name such as web-01.example.net.

If the old hostname appears in DNS records, SSH trust, TLS certificates, monitoring targets, or configuration-management data, update those references separately before treating the rename as complete.
Confirm that the running host and the persistent hostname file now show the new name.
```
$ hostnamectl --static
web-01

$ hostname
web-01

$ cat /etc/hostname
web-01
```
If /etc/hostname does not match hostnamectl –static, or the name reverts later, another management layer such as cloud-init or configuration management is rewriting it.
Check whether Ubuntu still maps the old short name on 127.0.1.1 in /etc/hosts.
```
$ grep -n '127.0.1.1' /etc/hosts
2:127.0.1.1 host
```
If this command prints nothing, there is no host-specific local mapping to change on this system.
Update the 127.0.1.1 line in /etc/hosts if the previous step still showed the old name.
```
$ sudoedit /etc/hosts
```
```
127.0.0.1 localhost
127.0.1.1 web-01
```
Keep the localhost entries unchanged and replace only the host-specific hostname fields on the 127.0.1.1 line.

Related: How to edit the hosts file in Linux