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So, What I'm trying to do is simply change the hostname permanently. I can update the hostname but when a reboot is issued the original hostname is used!

I'm aware there is a file hostname located at: /etc/hostname. I update this file and issue a reboot, however the hostname is back to the previous setting!

What I've tried:

  1. Updating /etc/hosts file newhostname
  2. Updating hosts file - 127.0.0.1 newhostname
  3. reboot

I've also tried with sudo user and root!

Why is this happening?!

Thanks for any advice or suggestions, I feel like I've tried every other solution with no avail.

EDIT:

I've just updated the /etc/hostname file on a VM running debian 7 locally and it works as expected. Why doesn't this work when connected to a remote server with SSH?

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5
  • Is the server using dhcp?
    – jordanm
    Commented May 4, 2015 at 13:24
  • Not enough rep to add a comment. Have you tried hostname.sh?
    – DCJeff
    Commented May 4, 2015 at 13:29
  • Not using dhcp.
    – dan983
    Commented May 4, 2015 at 13:30
  • How are you checking what the hostname is? Are you just going off of what the prompt says? When you SSH into the server, do echo $PS1. I highly doubt someone has changed it, but you never know ....
    – Safado
    Commented May 4, 2015 at 14:58
  • 1
    I just issue 'hostname' after the reboot and it shows the old host name. It's a bit strange because it doesn't happen when I change the hostname on a VM.
    – dan983
    Commented May 4, 2015 at 15:07

4 Answers 4

Reset to default
10 
hostnamectl set-hostname servername.example.com

That's for RHEL 7 that is.

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1
  • Same happened to my Debian setups. thx.
    – m3nda
    Commented Feb 25, 2019 at 12:40
5

Another reason why the host name gets reset could be the cloud-init package. This package is used to provision a host and can also be used to set the systems host name.

In the case of my Ubuntu system the preserve_hostname option was set to false in the file /etc/cloud/cloud.cfg. Setting this option to true, will let a newly set host name survive a reboot.

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  • I deployed a Debian image to OCI and was having this issue. This solutions was the fix to my problem. Thank you!
    – Max Kulik
    Commented Dec 15, 2022 at 22:16
4

/etc/hosts is meant as a first-step for DNS resolution. If you're trying to reach a host that's present there, it will use that record instead of querying DNS.

As you've discovered, /etc/hostname is one option for hostname changes in Debian. In RHEL6, it's /etc/sysconfig/network, and in RHEL7 it's either the hostnamectl command or /etc/hostname.

Changing hostnames on Linux hosts can vary by distribution and release, so it's best to Google the procedure for your particular platform.

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3

Try setting runtime kernel parameter

sudo bash -c "echo 'kernel.hostname = YOUR_HOSTNAME' >> /etc/sysctl.conf"

Apply your changes with

sudo sysctl -p

Now simply, logout and log back in, your hostname should be the one you applied.

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