How to Change Hostname on Debian 11

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Displaying the Current Hostname

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To find out your current system name by running the following command.

hostnamectl

Output:

root@server:~# hostnamectl
   Static hostname: Debian11
   Pretty hostname: crowncloud
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 39941301335d45acb6747d0b884bd638
           Boot ID: 1806121a0c0443978ee6d51db83b308e
    Virtualization: kvm
  Operating System: Debian GNU/Linux 11 (bullseye)
            Kernel: Linux 5.10.0-8-amd64
      Architecture: x86-64

Changing the System Hostname

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Now that you know the current hostname, you can change the hostname by using the following command and Optionally you can also set the pretty hostname as follows.

hostnamectl set-hostname crowncloud.net

hostnamectl set-hostname "crowncloud production server" --pretty

And also /etc/hosts file should be edited to successfully change Debian server name.

vi /etc/hosts

Output:

127.0.0.1       localhost
127.0.1.1       crowncloud.net

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Then replace the old name with the new, then save the file and exit.

Debian servers might need to install cloud-init. If it is installed you will also need to edit the cloud.cfg file.

apt install cloud-init

Once the cloud-init is installed need to find "preserve_hostname: false" line in the follwoing configuration file "/etc/cloud/cloud.cfg" and change it to true.

vi /etc/cloud/cloud.cfg

preserve_hostname: true

Save the file and exit,

Verify the change

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To verify the hostname has been fully changed, enter the "hostnamectl" command:

hostnamectl

Output:

root@server:~# hostnamectl
   Static hostname: crowncloud.net
   Pretty hostname: crowncloud production server
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 39941301335d45acb6747d0b884bd638
           Boot ID: 1806121a0c0443978ee6d51db83b308e
    Virtualization: kvm
  Operating System: Debian GNU/Linux 11 (bullseye)
            Kernel: Linux 5.10.0-8-amd64
      Architecture: x86-64