How Can I Change Hostname on My Linux Server Ubuntu OS ?

When managing Ubuntu servers, setting a clear and accurate hostname helps identify your machine on a network and simplifies administration. Whether you're preparing a staging environment or deploying a production node, changing the hostname is a quick and essential task.

This guide walks you through how to view and change the hostname on an Ubuntu Server (16.04 and above).

Step 1: Check the Current Hostname

Run the following command to see your current hostname:

hostname

For more detailed information:

hostnamectl

Example output:

Static hostname: ubuntu-server
Pretty hostname: Ubuntu Server

Step 2: Change the Hostname (Ubuntu 16.04+ with systemd)

Ubuntu uses hostnamectl, a systemd tool that simplifies hostname changes.

Run the command:

sudo hostnamectl set-hostname your-new-hostname

Replace your-new-hostname with the name you want (e.g. web-node-01).

Example:

sudo hostnamectl set-hostname web-node-01

Step 3: Update /etc/hosts File

To avoid issues with local resolution (e.g. sudo delays or errors), update your /etc/hosts file:

1. Open the file with a text editor:

sudo nano /etc/hosts

2. Look for a line like:

127.0.1.1    old-hostname

3. Change old-hostname to your new one:

127.0.1.1    web-node-01

Save and exit (Ctrl + O, Enter, Ctrl + X).

Step 4: Verify the Change

You can verify that your hostname has changed with:

hostname
hostnamectl

Expected output:

Static hostname: web-node-01

You may also see the new hostname in your shell prompt (after re-logging or opening a new terminal).

(Optional) Reboot

Though not required, rebooting ensures that all services reflect the new hostname:

sudo reboot

• Hostnames should contain only letters, numbers, and hyphens, and must not begin or end with a hyphen.
• Avoid using spaces or special characters.
• In cloud environments (AWS, Azure, etc.), hostnames may revert after reboot unless configured in cloud-init or provider settings.

Example Use Cases

Conclusion

Changing the hostname on Ubuntu is fast, simple, and requires no advanced setup. Using hostnamectl, you can update your server's identity in seconds and ensure consistency across your infrastructure.

For automated deployments, you can even include hostname configuration in your cloud-init scripts or provisioning tools like Ansible.