Knowledgebase

Introduction

When you deploy a new RCS cloud server, you can set the Server Hostname on the deployment page. Later, if you decide to change the server name, you can use the Change Hostname form in the server's Settings menu.

However, if you use this method to change the hostname, RCS destroys the cloud server and reinstalls a new operating system image, which wipes all the data on the server.

How to Change Hostname without Erasing the Server

1. Locate your operating system from the list below.
2. Follow the steps for your operating system.
3. (optional) Update your DNS. This procedure does not change your DNS name. If you use DNS and need to change that name, follow the guides from your DNS host. If you use RCS DNS, you'll find our guide here.

This guide uses example names: olddog for the old name and newtricks for the new.

Change Hostname on AlmaLinux, CentOS, Fedora, Rocky Linux, and VzLinux

This section applies to:

• AlmaLinux
• CentOS 7 and later
• Fedora 31 and later
• Rocky Linux
• VzLinux

Procedure:

1. Important: Disable automatic hostname updates from cloud-init by editing /etc/cloud/cloud.cfg.

   $ sudo nano /etc/cloud/cloud.cfg
   

   Change the value of preserve_hostname to true.

   preserve_hostname: true
   

   Save and exit the file.

2. Check the current hostname with the hostname command.

   $ hostname
   olddog
   

   You can also use hostnamectl.

   $ hostnamectl
   Static hostname: olddog
   

3. Change the hostname to newtricks.

   $ sudo hostnamectl set-hostname newtricks
   

4. Change any instances of the old hostname in /etc/hosts. If you have a DNS name pointed to this instance, it's also best practice to set that name here.

   $ sudo nano /etc/hosts
   

   Example of old hosts file:

   127.0.0.1 olddog
   ::1       olddog
   

   Example of new hosts file.

   127.0.0.1 newtricks newtricks.example.com
   ::1       newtricks newtricks.example.com
   

5. Reboot the server.

6. Test your change with hostnamectl and hostname.

   $ hostnamectl
    Static hostname: newtricks
   
   $ hostname
   newtricks
   
   $ hostname -a
   newtricks.example.com
   

Change Hostname on Arch Linux

This section applies to any recently updated version of Arch Linux.

Procedure:

1. Important: Disable automatic hostname updates from cloud-init by editing /etc/cloud/cloud.cfg.

   $ sudo nano /etc/cloud/cloud.cfg
   

   Change the value of preserve_hostname to true.

   preserve_hostname: true
   

   Save and exit the file.

2. Check the current hostname using the hostnamectl tool.

   $ hostnamectl
      Static hostname: olddog
   

   Check the hosts file with the getent tool.

   $ getent hosts
   127.0.0.1       localhost
   127.0.0.1       localhost
   127.0.1.1       olddog.localdomain olddog
   

3. Change the hostname to newtricks.

   $ sudo hostnamectl set-hostname newtricks
   

4. Change any instances of the old hostname in /etc/hosts. If you have a DNS name pointed to this instance, it's also best practice to set that name here.

   $ sudo vim /etc/hosts
   

   Example of old hosts file:

   127.0.0.1        localhost
   ::1              localhost
   127.0.1.1        olddog.localdomain olddog
   

   Example of new hosts file:

   127.0.0.1        localhost
   ::1              localhost
   127.0.1.1        newtricks.localdomain newtricks
   

5. Either reboot the server or log out and back in again to your user session.

6. Test the change with the hostnamectl tool.

   $ hostnamectl
      Static hostname: newtricks
   

7. Test the change with the getent tool.

   $ getent hosts
   127.0.0.1       localhost
   127.0.0.1       localhost
   127.0.1.1       newtricks.localdomain newtricks
   

統 Note: For a system with a permanent IP address, that permanent IP address should be used instead of 127.0.1.1. The order of hostnames in /etc/hosts is significant. The first string is the canonical hostname. Subsequent names on the same line are aliases.

Change Hostname on Debian & Ubuntu

This section applies to:

• Debian GNU/Linux 9 "Stretch" and later
• Ubuntu version 16.04 and later

Procedure:

1. Important: Disable automatic hostname updates from cloud-init by editing /etc/cloud/cloud.cfg.

   $ sudo nano /etc/cloud/cloud.cfg
   

   Change the value of preserve_hostname to true.

   preserve_hostname: true
   

   Save and exit the file.

2. Check the current hostname with the hostname command.

   $ hostname
   olddog
   

   You can also use hostnamectl.

   $ hostnamectl
      Static hostname: olddog
   

3. Change the hostname to newtricks.

   $ sudo hostnamectl set-hostname newtricks
   

4. Change any instances of the old hostname in /etc/hosts. If you have a DNS name pointed to this instance, it's also best practice to set that name here.

   $ sudo nano /etc/hosts
   

   Example of old hosts file:

   127.0.0.1 localhost
   127.0.1.1 olddog
   

   Example of new hosts file.

   127.0.0.1 localhost
   127.0.1.1 newtricks.example.com newtricks
   

5. Reboot the server.

6. Test your change with hostnamectl and hostname.

   $ hostnamectl
      Static hostname: newtricks
   
   $ hostname
   newtricks
   
   $ hostname -f
   newtricks.example.com
   

Change Hostname on Fedora CoreOS

Fedora CoreOS (FCOS) uses the Ignition file to set the server hostname. If you decide to rename a running server, you'll need to update the name from the command line.

1. Connect to your FCOS instance and change to the root user.

   $ sudo su - root
   

2. Check the hostname with hostname.

   # hostname
   olddog
   

   You can also use hostnamectl.

   # hostnamectl
    Static hostname: olddog
   

3. Change the hostname to newtricks.

   # hostnamectl set-hostname newtricks
   

4. Reboot the server.

   # reboot
   

5. Test your change with hostnamectl and hostname.

   $ hostnamectl
      Static hostname: newtricks
   
   $ hostname
   newtricks
   

Change Hostname on FreeBSD

This section applies to all versions of FreeBSD.

Procedure:

1. Check the current hostname with the hostname command.

   $ hostname
   olddog
   

2. Change the hostname to newtricks using a text editor.

   • Change all occurrences in /etc/rc.conf.
   • Change all occurrences in /etc/hosts.

3. Reboot the server.

4. Test your change with hostname.

   $ hostname
   newtricks
   

Change Hostname on OpenBSD

This section applies to all versions of OpenBSD.

Procedure:

1. Check the current hostname with the hostname command.

   $ hostname
   olddog
   

2. Change the hostname to newtricks using a text editor:

   • Change all occurrences in /etc/myname.
   • Change all occurrences in /etc/hosts.

3. Reboot the server.

4. Test your change with hostname.

   $ hostname
   newtricks
   

Change Hostname on Windows

This section applies to Windows Server 2012 and later.

How to Change the Hostname in PowerShell

1. Open an elevated PowerShell. If you are in standard PowerShell, elevate your access as shown:

   PS C:\> Start-Process PowerShell -Verb Runas
   

2. Check the hostname with $env:computername.

   PS C:\> $env:computername
   OLDDOG
   

3. Change the hostname to NEWTRICKS. Using the -Restart parameter will also immediately restart the server. Full documentation on the Rename-Computer cmdlet is available at Microsoft.

   PS C:\> Rename-Computer -NewName "NEWTRICKS" -Restart
   

4. Verify the hostname has changed with $env:computername.

   PS C:\> $env:computername
   NEWTRICKS
   

How to Change the Hostname with the GUI

1. Log in to the server via RDP.
2. Navigate to the "This PC" screen and click "System properties".
3. Click "Change settings" next to the current computer name.
4. Click the "Change" button.
5. Enter a new computer name and confirm by clicking "OK".
6. Restart the server.

About Windows Hostnames

A hostname is what identifies a server. Most Windows Server users name their servers with the hostname consisting of two parts: role.domain. The role part is the role installed on the server, followed by the number. For example, if dc01 is the first server that acts as a DC in this particular network, Windows makes this an FQDN by putting the Active Directory domain as the domain part. For example, if this is the third web server in this network, and the domain is example.com, the hostname would be:

ws03.example.com

Note that changing the hostname on Windows Server may conflict with some installed roles. Changing the hostname before installing roles on the server is a good idea. For recovery purposes, make a snapshot first if you decide to change the hostname on a Windows Server.