How to Set or Change Hostname in CentOS 7?

The hostname plays a crucial role in identifying a server on a network and generating the fully qualified domain name (FQDN) for the system. In CentOS 7, changing the hostname involves modifying key system files and applying the changes properly.

This process requires updating the /etc/hostname file and the /etc/hosts file to ensure the system recognizes the new identifier. After making these changes, a system reboot ensures they take effect across all services and networking components.

Step 1 Check the Current Hostname

Before making changes, verify the current hostname by opening a terminal and running the following command

hostname

This displays the current hostname of the system

[root@server ~]# hostname
server.tutorialpoint.com

You can also use hostnamectl to get detailed hostname information

hostnamectl status

Step 2 Change the Hostname File

Edit the hostname file located at /etc/hostname using a text editor. This file contains the current hostname of the system

sudo vi /etc/hostname

Replace the existing hostname with your desired new hostname. For example, to change from server.tutorialpoint.com to webserver.tutorialpoint.com

webserver.tutorialpoint.com

Save and exit the file by pressing Esc, then typing :wq and pressing Enter.

Alternative Method Using hostnamectl

CentOS 7 provides the hostnamectl command as a modern alternative

sudo hostnamectl set-hostname webserver.tutorialpoint.com

Step 3 Update the Hosts File

The /etc/hosts file maps hostnames to IP addresses and must be updated to include the new hostname

sudo vi /etc/hosts

Locate the line containing 127.0.0.1 and add your new hostname. The updated line should look like this

127.0.0.1 localhost.localdomain localhost webserver.tutorialpoint.com

This ensures the system can properly resolve the new hostname to its IP address, especially important in networked environments.

Step 4 Apply Changes

To apply the hostname changes without rebooting, restart the systemd-hostnamed service

sudo systemctl restart systemd-hostnamed

For a complete system restart, use

sudo reboot

Verification

After the changes are applied, verify the new hostname

hostname

Expected output

[root@webserver ~]# hostname
webserver.tutorialpoint.com

Use hostnamectl for detailed verification

hostnamectl status

Key Points

• Persistent Changes Modifying /etc/hostname ensures the hostname persists across reboots.

• Network Resolution Updating /etc/hosts allows proper hostname-to-IP mapping.

• Modern Tools The hostnamectl command provides a streamlined approach for CentOS 7.

• Service Dependencies Some services may need restart to recognize the new hostname.

Conclusion

Changing the hostname in CentOS 7 is straightforward and involves updating the /etc/hostname and /etc/hosts files. Using modern tools like hostnamectl simplifies this process further. A properly configured hostname improves server management, prevents network conflicts, and enhances system security by providing clear server identification.