35_1: Overview

This document provides detailed instructions on how to rename the hostname of a Linux instance, which affects the name displayed in PuTTY sessions. If you have renamed your instance in OCI but the old hostname is still shown, follow these steps to resolve the issue.

35_2: Check the Current Hostname

• OCI Instance has been renamed as Application_Server.

• Open your terminal or PuTTY session and run:

hostname

This will display the current hostname of the system.

35_3: Update the Hostname

You can change the hostname temporarily or permanently.

35_3_1: Temporary Change

To change the hostname temporarily (until the next reboot):

sudo hostnamectl set-hostname <new-hostname>

sudo hostnamectl set-hostname Application_Server

Replace with your desired hostname.

35_3_2: Permanent Change

To make the hostname change permanent:

Edit /etc/hostname:

sudo nano /etc/hostname

Replace the existing hostname with your desired new hostname. For example:

Edit old-hostname

Change to: new-hostname

Edit /etc/hosts: Open the /etc/hosts file:

sudo nano /etc/hosts

Find the line:

IP Address old-hostname

Replace old-hostname with the new hostname:

IP Address new-hostname

ControlKey + O to write and enter ControlKey + x to exit

Save and exit both files.

35_4: Apply the Changes

To apply the changes without rebooting the system:

sudo hostnamectl set-hostname new-hostname

Verify that the hostname has been updated:

hostname

Alternatively, reboot the system to ensure all services recognize the new hostname:

sudo reboot

35_5: Verify in PuTTY

Disconnect your current PuTTY session.

Reconnect to your instance using PuTTY.

The new hostname should now appear in the terminal prompt.

35_6: Troubleshooting

Ensure you have administrative (sudo) privileges to modify system files.

Double-check that the hostnamectl command does not throw any errors.

If changes don’t persist after a reboot, confirm the edits in /etc/hostname and /etc/hosts are correctly saved.